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Gaizauskaite Z, Zvirdauskiene R, Svazas M, Basinskiene L, Zadeike D. Optimised Degradation of Lignocelluloses by Edible Filamentous Fungi for the Efficient Biorefinery of Sugar Beet Pulp. Polymers (Basel) 2024; 16:1178. [PMID: 38732647 PMCID: PMC11085495 DOI: 10.3390/polym16091178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 04/17/2024] [Accepted: 04/18/2024] [Indexed: 05/13/2024] Open
Abstract
The degradation of the complex structure of lignocellulosic biomass is important for its further biorefinery to value-added bioproducts. The use of effective fungal species for the optimised degradation of biomass can promote the effectiveness of the biorefinery of such raw material. In this study, the optimisation of processing parameters (temperature, time, and s/w ratio) for cellulase activity and reducing sugar (RS) production through the hydrolysis of sugar beet pulp (SBP) by edible filamentous fungi of Aspergillus, Fusarium, Botrytis, Penicillium, Rhizopus, and Verticillium spp. was performed. The production of RS was analysed at various solid/water (s/w) ratios (1:10-1:20), different incubation temperatures (20-35 °C), and processing times (60-168 h). The Aspergillus niger CCF 3264 and Penicillium oxalicum CCF 3438 strains showed the most effective carboxymethyl cellulose (CMC) degrading activity and also sugar recovery (15.9-44.8%) from SBP biomass in the one-factor experiments. Mathematical data evaluation indicated that the highest RS concentration (39.15 g/100 g d.w.) and cellulolytic activity (6.67 U/g d.w.) could be achieved using A. niger CCF 3264 for the degradation of SBP at 26 °C temperature with 136 h of processing time and a 1:15 solid/water ratio. This study demonstrates the potential of fungal degradation to be used for SBP biorefining.
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Affiliation(s)
- Zydrune Gaizauskaite
- Department of Food Science and Technology, Faculty of Chemical Technology, Kaunas University of Technology, 50254 Kaunas, Lithuania; (R.Z.); (L.B.)
- Food Institute, Kaunas University of Technology, 50254 Kaunas, Lithuania
| | - Renata Zvirdauskiene
- Department of Food Science and Technology, Faculty of Chemical Technology, Kaunas University of Technology, 50254 Kaunas, Lithuania; (R.Z.); (L.B.)
| | - Mantas Svazas
- Department of Applied Economics, Finance and Accounting, Agriculture Academy of Vytautas Magnus University, 53361 Kaunas, Lithuania;
| | - Loreta Basinskiene
- Department of Food Science and Technology, Faculty of Chemical Technology, Kaunas University of Technology, 50254 Kaunas, Lithuania; (R.Z.); (L.B.)
| | - Daiva Zadeike
- Department of Food Science and Technology, Faculty of Chemical Technology, Kaunas University of Technology, 50254 Kaunas, Lithuania; (R.Z.); (L.B.)
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Liu S, Quan L, Yang M, Wang D, Wang YZ. Regulation of cellulase production via calcium signaling in Trichoderma reesei under PEG8000 stress. Appl Microbiol Biotechnol 2024; 108:178. [PMID: 38276978 PMCID: PMC10817842 DOI: 10.1007/s00253-023-12901-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 10/21/2023] [Accepted: 11/05/2023] [Indexed: 01/27/2024]
Abstract
In this study, the effect of polyethylene glycol 8000 (PEG8000) stress on cellulase biosynthesis in Trichoderma reesei CICC2626 via calcium signaling was investigated, and a plausible mechanism by which intracellular Ca2+ regulates the transcription of cellulase genes was proposed. The results indicated that the total cellulase (filter paper-hydrolyzing activity [FPase]), endoglucanase (carboxymethyl cellulase activity [CMCase]), and β-glucosidase activities of the strain were 1.3-, 1.2-, and 1.3-fold higher than those of the control (no PEG8000 addition) at a final concentration of 1.5% (w/v) PEG8000. Moreover, the transcriptional levels of cellulase genes, protein concentrations, and biomass increased. With the synergistic use of commercial cellulase and T. reesei CICC2626 cellulase to hydrolyze alkali-pretreated rice straw, the released reducing sugar concentration reached 372.7 mg/g, and the cellulose content (22.7%, 0.32 g) was significantly lower than the initial content (62.5%, 1.88 g). Transcriptome data showed that 12 lignocellulose degradation-related genes were significantly upregulated in the presence of 1.5% PEG8000. Furthermore, the addition of Ca2+ inhibitors and deletion of crz1 (calcineurin-responsive zinc finger 1-encoding gene, which is related to the calcium signaling pathway) demonstrated that calcium signaling plays a dominant role in PEG8000-induced cellulase genes overexpression. These results revealed a link between PEG8000 induction and calcium signaling transduction in T. reesei CICC2626. Moreover, this study also provides a novel inducer for enhanced cellulase production. KEY POINTS: • Cellulase biosynthesis in Trichoderma reesei could be enhanced by PEG8000 • PEG8000 could induce a cytosolic Ca2+ burst in Trichoderma reesei • The activated calcium signaling was involved in cellulase biosynthesis.
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Affiliation(s)
- Shuai Liu
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, College of Bioengineering, Chongqing University, Chongqing, 400030, China
| | - Lin Quan
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, College of Bioengineering, Chongqing University, Chongqing, 400030, China
| | - Mei Yang
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, College of Bioengineering, Chongqing University, Chongqing, 400030, China
| | - Dan Wang
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, 400044, China
| | - Yong-Zhong Wang
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, College of Bioengineering, Chongqing University, Chongqing, 400030, China.
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de Araujo Ribeiro GC, de Assis SA. β-glucosidases from Saccharomyces cerevisiae: production, protein precipitation, characterization, and application in the enzymatic hydrolysis of delignified sugarcane bagasse. Prep Biochem Biotechnol 2024; 54:317-327. [PMID: 38178713 DOI: 10.1080/10826068.2023.2238290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2024]
Abstract
β-glucosidase is an essential enzyme for the enzymatic hydrolysis of lignocellulosic biomass, as it catalyzes the final stage of cellulose breakdown, releasing glucose. This paper aims to produce β-glucosidase from Saccharomyces cerevisiae and evaluate the enzymatic degradation of delignified sugarcane bagasse. S. cerevisiae was grown in yeast peptone dextrose medium. Partial purification of the enzyme was achieved through precipitating proteins with ethanol, and the optimal activity was measured by optimizing pH and temperature. The effects of ions, glucose tolerance, and heat treatment were evaluated. Delignified sugarcane bagasse was hydrolyzed by the enzyme. β-glucosidase showed a specific activity of 14.0712 ± 0.0207 U mg-1. Partial purification showed 1.22-fold purification. The optimum pH and temperature were 6.24 and 54 °C, respectively. β-glucosidase showed tolerance to glucose, with a relative activity of 71.27 ± 0.16%. Thermostability showed a relative activity of 58.84 ± 0.91% at 90 °C. The hydrolysis of delignified sugarcane bagasse showed a conversion rate of 87.97 ± 0.10% in the presence of Zn2+, an ion that promoted the highest increase in enzymatic activity. S. cerevisiae produced an extracellular β-glucosidase with good stability at pH and temperatures conventionally applied in the hydrolysis of lignocellulosic biomass, showing viability for industrial application.
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de Araujo Ribeiro GC, Assis SAD. Production of β-glucosidase by Rhodotorula oryzicola and use of enzyme for hydrolysis of sugarcane bagasse delignified. JOURNAL OF FOOD SCIENCE AND TECHNOLOGY 2023; 60:2761-2771. [PMID: 37711566 PMCID: PMC10497474 DOI: 10.1007/s13197-023-05783-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Revised: 05/10/2023] [Accepted: 06/01/2023] [Indexed: 09/16/2023]
Abstract
Bioethanol is obtained by hydrolysis of sugarcane bagasse by cellulases. Commercial cellulases are expensive and have a low concentration of β-glucosidase (EC 3.2.1.21), which decrease hydrolysis efficiency. The present work aims to produce supernatant rich in β-glucosidase (BGL) using the yeast Rhodotorula oryzicola and apply it in the hydrolysis of delignified sugarcane bagasse. Yeast fermented in a modified YPD (Yeast Peptone Dextrose) medium with 0.5% (w/v) cellobiose and 1.0% (w/v) glucose produced BGL with a specific activity of 1.44 ± 0.013 U/mg. Partial purification of BGL by acetone showed a specific activity of 3.48 U/mg. The optimum pH and temperature were 6.02 and 65 °C, respectively. BGL partially purified (BGLppR.oryzicola) by acetone showed tolerance to glucose, with a relative activity of 82.89 ± 0.11%. The activity increased with the addition of iron sulfate and zinc sulfate and decreased with manganese sulfate. BGL partially purified was thermal stable, with a relative activity of 85.59% after 60 min at 90 °C. BGL partially purified applied in the hydrolysis of sugarcane bagasse delignified with 3% (w/w) NaOH + 6% (w/w) Na2SO3 showed a conversion rate of 72.46 ± 1.60%. The results showed that BGL partially purified is a glucose tolerant cellulase of low-cost, promising the application of bioethanol production.
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Affiliation(s)
- Geise Camila de Araujo Ribeiro
- Health Department, State University of Feira de Santana, Transnordestina Ave., Km 0, BR 116, Feira de Santana, Bahia 44036-900 Brazil
| | - Sandra Aparecida de Assis
- Health Department, State University of Feira de Santana, Transnordestina Ave., Km 0, BR 116, Feira de Santana, Bahia 44036-900 Brazil
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Characterization of a New Glucose-Tolerant GH1 β-Glycosidase from Aspergillus fumigatus with Transglycosylation Activity. Int J Mol Sci 2023; 24:ijms24054489. [PMID: 36901919 PMCID: PMC10003650 DOI: 10.3390/ijms24054489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/17/2023] [Accepted: 02/20/2023] [Indexed: 03/02/2023] Open
Abstract
Concern over environmental impacts has spurred many efforts to replace fossil fuels with biofuels such as ethanol. However, for this to be possible, it is necessary to invest in other production technologies, such as second generation (2G) ethanol, in order to raise the levels of this product and meet the growing demand. Currently, this type of production is not yet economically feasible, due to the high costs of the enzyme cocktails used in saccharification stage of lignocellulosic biomass. In order to optimize these cocktails, the search for enzymes with superior activities has been the goal of several research groups. For this end, we have characterized the new β-glycosidase AfBgl1.3 from A. fumigatus after expression and purification in Pichia pastoris X-33. Structural analysis by circular dichroism revealed that increasing temperature destructured the enzyme; the apparent Tm value was 48.5 °C. The percentages of α-helix (36.3%) and β-sheet (12.4%) secondary structures at 25 °C were predicted. Biochemical characterization suggested that the optimal conditions for AfBgl1.3 were pH 6.0 and temperature of 40 °C. At 30 and 40 °C, the enzyme was stable and retained about 90% and 50% of its activity, respectively, after pre-incubation for 24 h. In addition, the enzyme was highly stable at pH between 5 and 8, retaining over 65% of its activity after pre-incubation for 48 h. AfBgl1.3 co-stimulation with 50-250 mM glucose enhanced its specific activity by 1.4-fold and revealed its high tolerance to glucose (IC50 = 2042 mM). The enzyme was active toward the substrates salicin (495.0 ± 49.0 U mg-1), pNPG (340.5 ± 18.6 U mg-1), cellobiose (89.3 ± 5.1 U mg-1), and lactose (45.1 ± 0.5 U mg-1), so it had broad specificity. The Vmax values were 656.0 ± 17.5, 706.5 ± 23.8, and 132.6 ± 7.1 U mg-1 toward p-nitrophenyl-β-D-glucopyranoside (pNPG), D-(-)-salicin, and cellobiose, respectively. AfBgl1.3 displayed transglycosylation activity, forming cellotriose from cellobiose. The addition of AfBgl1.3 as a supplement at 0.9 FPU/g of cocktail Celluclast® 1.5L increased carboxymethyl cellulose (CMC) conversion to reducing sugars (g L-1) by about 26% after 12 h. Moreover, AfBgl1.3 acted synergistically with other Aspergillus fumigatus cellulases already characterized by our research group-CMC and sugarcane delignified bagasse were degraded, releasing more reducing sugars compared to the control. These results are important in the search for new cellulases and in the optimization of enzyme cocktails for saccharification.
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Zhang X, Chen X, Li S, Bello A, Liu J, Gao L, Fan Z, Wang S, Liu L, Ma B, Li H. Mechanism of differential expression of β-glucosidase genes in functional microbial communities in response to carbon catabolite repression. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:3. [PMID: 35418139 PMCID: PMC8756671 DOI: 10.1186/s13068-021-02101-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 12/29/2021] [Indexed: 11/10/2022]
Abstract
Abstract
Background
β-Glucosidase is the rate-limiting enzyme of cellulose degradation. It has been stipulated and established that β-glucosidase-producing microbial communities differentially regulate the expression of glucose/non-glucose tolerant β-glucosidase genes. However, it is still unknown if this differential expression of functional microbial community happens accidentally or as a general regulatory mechanism, and of what biological significance it has. To investigate the composition and function of microbial communities and how they respond to different carbon metabolism pressures and the transcriptional regulation of functional genes, the different carbon metabolism pressure was constructed by setting up the static chamber during composting.
Results
The composition and function of functional microbial communities demonstrated different behaviors under the carbon metabolism pressure. Functional microbial community up-regulated glucose tolerant β-glucosidase genes expression to maintain the carbon metabolism rate by enhancing the transglycosylation activity of β-glucosidase to compensate for the decrease of hydrolysis activity under carbon catabolite repression (CCR). Micrococcales play a vital role in the resistance of functional microbial community under CCR. The transcription regulation of GH1 family β-glucosidase genes from Proteobacteria showed more obvious inhibition than other phyla under CCR.
Conclusion
Microbial functional communities differentially regulate the expression of glucose/non-glucose tolerant β-glucosidase genes under CCR, which is a general regulatory mechanism, not accidental. Furthermore, the differentially expressed β-glucosidase gene exhibited species characteristics at the phylogenetic level.
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Efficient Corncob Biorefinery for Ethanol Initiated by a Novel Pretreatment of Densifying Lignocellulosic Biomass with Sulfuric Acid. FERMENTATION-BASEL 2022. [DOI: 10.3390/fermentation8110661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Corncob is a potential feedstock for biorefineries to produce cellulosic ethanol and other chemicals. Densifying lignocellulosic biomass with chemicals followed by autoclave (DLCA) has been confirmed an efficient and economical pretreatment method, and it was applied in the present work for conversion of corncob to bioethanol. The dosage of sulfuric acid, solid loading of biomass, and autoclave time for pretreatment were investigated. Enzymatic hydrolysis at 25–35% solids loadings resulted in 91–97% sugar conversions. Fermentation of the resulted hydrolysates went well with the highest ethanol titer reaching 75.71 g/L at 35% solid loading. Simultaneous saccharification and co-fermentation was applied to further improve xylose consumption at high solids loadings and the ethanol titer was enhanced to 82.0 g/L at 35% solid loading with an ethanol yield of 21.67 kg/100 kg corncob. This study demonstrated DLCA provided a highly digestible and highly fermentable corncob for biorefinery.
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Improvement of Lignocellulolytic Enzyme Production Mediated by Calcium Signaling in Bacillus subtilis Z2 under Graphene Oxide Stress. Appl Environ Microbiol 2022; 88:e0096022. [PMID: 36121214 PMCID: PMC9552604 DOI: 10.1128/aem.00960-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
An increase in exoenzyme production can be enhanced by environmental stresses such as graphene oxide (GO) stress, but the link between the two events is still unclear. In this work, the effect of GO as an environmental stress factor on exoenzyme (lignocellulolytic enzyme, amylase, peptidase, and protease) biosynthesis was investigated in Bacillus subtilis Z2, and a plausible mechanism by which cytosolic Ca2+ regulates lignocellulolytic enzyme production in B. subtilis Z2 subjected to GO stress was proposed. The filter paper-hydrolyzing (FPase [representing total cellulase]), carboxymethylcellulase (CMCase [representing endoglucanase]), and β-glucosidase activities and extracellular protein concentration of the wild-type strain under 10 μg/mL GO stress were 1.37-, 1.64-, 1.24-, and 1.16-fold those of the control (without GO stress), respectively. Correspondingly, the transcription levels of lignocellulolytic enzyme genes, cytosolic Ca2+ level, and biomass concentration of B. subtilis were all increased. With lignocellulolytic enzyme from B. subtilis used to hydrolyze alkali-pretreated rice straw, the released reducing sugar concentration reached 265.53 mg/g, and the removal rates of cellulose, hemicellulose, and lignin were 52.4%, 30.1%, and 7.5%, respectively. Furthermore, transcriptome data revealed that intracellular Ca2+ homeostasis played a key role in regulating the levels of gene transcription related to the synthesis of lignocellulolytic enzymes and exoenzymes. Finally, the use of Ca2+ inhibitors (LaCl3 and EDTA) and deletion of spcF (a calmodulin-like protein gene) further demonstrated that the overexpression of those genes was regulated via calcium signaling in B. subtilis subjected to GO stress. IMPORTANCE To effectively convert lignocellulose into fermentable sugars, high lignocellulolytic enzyme loading is needed. Graphene oxide (GO) has been shown to promote exoenzyme (lignocellulolytic enzyme, amylase, peptidase, and protease) production in some microorganisms; however, the regulatory mechanism of the biosynthesis of lignocellulolytic enzymes under GO stress remains unclear. In this work, the lignocellulolytic enzyme production of B. subtilis under GO stress was investigated, and the potential mechanism by which B. subtilis enhanced lignocellulolytic enzyme production through the calcium signaling pathway under GO stress was proposed. This work revealed the role of calcium signaling in the production of enzymes under external environmental stress and provided a direction to facilitate lignocellulolytic enzyme production by B. subtilis.
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Madhavan A, Arun KB, Sindhu R, Alphonsa Jose A, Pugazhendhi A, Binod P, Sirohi R, Reshmy R, Kumar Awasthi M. Engineering interventions in industrial filamentous fungal cell factories for biomass valorization. BIORESOURCE TECHNOLOGY 2022; 344:126209. [PMID: 34715339 DOI: 10.1016/j.biortech.2021.126209] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/18/2021] [Accepted: 10/20/2021] [Indexed: 05/15/2023]
Abstract
Filamentous fungi possess versatile capabilities for synthesizing a variety of valuable bio compounds, including enzymes, organic acids and small molecule secondary metabolites. The advancements of genetic and metabolic engineering techniques and the availability of sequenced genomes discovered their potential as expression hosts for recombinant protein production. Remarkably, plant-biomass degrading filamentous fungi show the unique capability to decompose lignocellulose, an extremely recalcitrant biopolymer. The basic biochemical approaches have motivated several industrial processes for lignocellulose biomass valorisation into fermentable sugars and other biochemical for biofuels, biomolecules, and biomaterials. The review gives insight into current trends in engineering filamentous fungi for enzymes, fuels, and chemicals from lignocellulose biomass. This review describes the variety of enzymes and compounds that filamentous fungi produce, engineering of filamentous fungi for biomass valorisation with a special focus on lignocellulolytic enzymes and other bulk chemicals.
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Affiliation(s)
- Aravind Madhavan
- Rajiv Gandhi Centre for Biotechnology, Jagathy, Trivandrum 695 014, India.
| | - K B Arun
- Rajiv Gandhi Centre for Biotechnology, Jagathy, Trivandrum 695 014, India
| | - Raveendran Sindhu
- Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Trivandrum 695 019, India
| | - Anju Alphonsa Jose
- Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Trivandrum 695 019, India
| | | | - Parameswaran Binod
- Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Trivandrum 695 019, India
| | - Ranjna Sirohi
- Department of Chemical & Biological Engineering, Korea University, Seoul 136713, Republic of Korea; Centre for Energy & Environmental Sustainability, Lucknow 226001. Uttar Pradesh, India
| | - R Reshmy
- Post Graduate and Research Department of Chemistry, Bishop Moore College, Mavelikara 690 110, Kerala, India
| | - Mukesh Kumar Awasthi
- College of Natural Resources and Environment, Northwest A & F University, Yangling, Shaanxi 712 100, PR China
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Unconventional β-Glucosidases: A Promising Biocatalyst for Industrial Biotechnology. Appl Biochem Biotechnol 2021; 193:2993-3016. [PMID: 33871765 DOI: 10.1007/s12010-021-03568-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 04/08/2021] [Indexed: 10/21/2022]
Abstract
β-Glucosidases primarily catalyze removal of terminal glucosyl residues from a variety of glucoconjugates and also perform transglycosylation and reverse hydrolysis. These catalytic properties can be readily exploited for degradation of lignocellulosic biomass as well as for pharmaceutical, food and flavor industries. β-Glucosidases have been either isolated in the native form from the producer organism or recombinantly expressed and gaged for their biochemical properties and substrate specificities. Although almond and Aspergillus niger have been instantly recognizable sources of β-glucosidases utilized for various applications, an intricate pool of novel β-glucosidases from different sources can provide their potent replacements. Moreover, one can envisage the better efficacy of these novel candidates in biofuel and biorefinery industries facilitating efficient degradation of biomass. This article reviews properties of the novel β-glucosidases such as glucose tolerance and activation, substrate specificity, and thermostability which can be useful for their applications in lignocellulose degradation, food industry, and pharmaceutical industry in comparison with the β-glucosidases from the conventional sources. Such β-glucosidases have potential for encouraging white biotechnology.
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Draft genome of the glucose tolerant β-glucosidase producing rare Aspergillus unguis reveals complete cellulolytic machinery with multiple beta-glucosidase genes. Fungal Genet Biol 2021; 151:103551. [PMID: 33737204 DOI: 10.1016/j.fgb.2021.103551] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 02/24/2021] [Accepted: 03/07/2021] [Indexed: 11/20/2022]
Abstract
Draft genome sequence of the glucose tolerant beta glucosidase (GT-BGL) producing rare fungus Aspergillus unguis NII 08,123 was generated through Next Generation Sequencing (NGS). The genome size of the fungus was estimated to be 37.1 Mb. A total of 3116 contigs were assembled using SPades, and 15,161 proteins were predicted using AUGUSTUS 3.1. Among them, 13,850 proteins were annotated using UniProt. Distribution of CAZyme genes specifically those encoding lignocellulose degrading enzymes were analyzed and compared with those from the industrial cellulase producer Trichoderma reesei in view of the huge differences in detectable enzyme activities between the fungi, despite the ability of A. unguis to grow on lignocellulose as sole carbon source. Full length gene sequence of the inducible GT-BGL could be identified through tracing back from peptide mass fingerprint. A total of 403 CAZymes were predicted from the genome, which includes 232 glycoside hydrolases (GHs), 12 carbohydrate esterases (CEs), 109 glycosyl transferases (GTs), 15 polysaccharide lyases (PLs), and 35 genes with auxiliary activities (AAs). The high level of zinc finger motif containing transcription factors could possibly hint a tight regulation of the cellulolytic machinery, which may also explain the low cellulase activities even when a complete repertoire of cellulase degrading enzyme genes are present in the fungus.
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Sreeja-Raju A, Christopher M, Kooloth-Valappil P, Kuni-Parambil R, Gokhale DV, Sankar M, Abraham A, Pandey A, Sukumaran RK. Penicillium janthinellum NCIM1366 shows improved biomass hydrolysis and a larger number of CAZymes with higher induction levels over Trichoderma reesei RUT-C30. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:196. [PMID: 33292411 PMCID: PMC7706291 DOI: 10.1186/s13068-020-01830-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 11/16/2020] [Indexed: 05/09/2023]
Abstract
BACKGROUND Major cost of bioethanol is attributed to enzymes employed in biomass hydrolysis. Biomass hydrolyzing enzymes are predominantly produced from the hyper-cellulolytic mutant filamentous fungus Trichoderma reesei RUT-C30. Several decades of research have failed to provide an industrial grade organism other than T. reesei, capable of producing higher titers of an effective synergistic biomass hydrolyzing enzyme cocktail. Penicillium janthinellum NCIM1366 was reported as a cellulase hyper producer and a potential alternative to T. reesei, but a comparison of their hydrolytic performance was seldom attempted. RESULTS Hydrolysis of acid or alkali-pretreated rice straw using cellulase enzyme preparations from P. janthinellum and T. reesei indicated 37 and 43% higher glucose release, respectively, with P. janthinellum enzymes. A comparison of these fungi with respect to their secreted enzymes indicated that the crude enzyme preparation from P. janthinellum showed 28% higher overall cellulase activity. It also had an exceptional tenfold higher beta-glucosidase activity compared to that of T. reesei, leading to a lower cellobiose accumulation and thus alleviating the feedback inhibition. P. janthinellum secreted more number of proteins to the extracellular medium whose total concentration was 1.8-fold higher than T. reesei. Secretome analyses of the two fungi revealed higher number of CAZymes and a higher relative abundance of cellulases upon cellulose induction in the fungus. CONCLUSIONS The results revealed the ability of P. janthinellum for efficient biomass degradation through hyper cellulase production, and it outperformed the established industrial cellulase producer T. reesei in the hydrolysis experiments. A higher level of induction, larger number of secreted CAZymes and a high relative proportion of BGL to cellulases indicate the possible reasons for its performance advantage in biomass hydrolysis.
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Affiliation(s)
- AthiraRaj Sreeja-Raju
- Biofuels and Biorefineries Section, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Industrial Estate, Pappanamcode, Thiruvananthapuram, 695019, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Meera Christopher
- Biofuels and Biorefineries Section, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Industrial Estate, Pappanamcode, Thiruvananthapuram, 695019, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Prajeesh Kooloth-Valappil
- Biofuels and Biorefineries Section, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Industrial Estate, Pappanamcode, Thiruvananthapuram, 695019, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Rajasree Kuni-Parambil
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, India
| | | | - Meena Sankar
- Biofuels and Biorefineries Section, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Industrial Estate, Pappanamcode, Thiruvananthapuram, 695019, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Amith Abraham
- Department of Chemical Engineering, Hanyang University, Seoul, Republic of Korea
| | - Ashok Pandey
- Centre for Innovation and Translational Research, CSIR-Indian Institute of Toxicology Research, Lucknow, India
| | - Rajeev K Sukumaran
- Biofuels and Biorefineries Section, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Industrial Estate, Pappanamcode, Thiruvananthapuram, 695019, India.
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
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13
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All4894 encoding a novel fasciclin (FAS-1 domain) protein of Anabaena sp. PCC7120 revealed the presence of a thermostable β-glucosidase. ALGAL RES 2020. [DOI: 10.1016/j.algal.2020.102036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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14
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Sun J, Ma Y, Xu X, Liu Z, Zou L. Molecular cloning and bioinformatics analyses of a GH3 beta-glucosidase from Auricularia heimuer. BIOTECHNOL BIOTEC EQ 2020. [DOI: 10.1080/13102818.2020.1807407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Affiliation(s)
- Jian Sun
- Department of Forest Protection, College of Forestry, Northeast Forestry University, Harbin, Heilongjiang, PR China
| | - Yisha Ma
- Department of Forest Protection, College of Forestry, Northeast Forestry University, Harbin, Heilongjiang, PR China
| | - Xinru Xu
- College of Life Science, Northeast Forestry University, Harbin, Heilongjiang, PR China
| | - Zengcai Liu
- Department of Forest Protection, College of Forestry, Northeast Forestry University, Harbin, Heilongjiang, PR China
| | - Li Zou
- Department of Forest Protection, College of Forestry, Northeast Forestry University, Harbin, Heilongjiang, PR China
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Mariano D, Pantuza N, Santos LH, Rocha REO, de Lima LHF, Bleicher L, de Melo-Minardi RC. Glutantβase: a database for improving the rational design of glucose-tolerant β-glucosidases. BMC Mol Cell Biol 2020; 21:50. [PMID: 32611314 PMCID: PMC7329481 DOI: 10.1186/s12860-020-00293-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 06/22/2020] [Indexed: 11/22/2022] Open
Abstract
Β-glucosidases are key enzymes used in second-generation biofuel production. They act in the last step of the lignocellulose saccharification, converting cellobiose in glucose. However, most of the β-glucosidases are inhibited by high glucose concentrations, which turns it a limiting step for industrial production. Thus, β-glucosidases have been targeted by several studies aiming to understand the mechanism of glucose tolerance, pH and thermal resistance for constructing more efficient enzymes. In this paper, we present a database of β-glucosidase structures, called Glutantβase. Our database includes 3842 GH1 β-glucosidase sequences collected from UniProt. We modeled the sequences by comparison and predicted important features in the 3D-structure of each enzyme. Glutantβase provides information about catalytic and conserved amino acids, residues of the coevolution network, protein secondary structure, and residues located in the channel that guides to the active site. We also analyzed the impact of beneficial mutations reported in the literature, predicted in analogous positions, for similar enzymes. We suggested these mutations based on six previously described mutants that showed high catalytic activity, glucose tolerance, or thermostability (A404V, E96K, H184F, H228T, L441F, and V174C). Then, we used molecular docking to verify the impact of the suggested mutations in the affinity of protein and ligands (substrate and product). Our results suggest that only mutations based on the H228T mutant can reduce the affinity for glucose (product) and increase affinity for cellobiose (substrate), which indicates an increment in the resistance to product inhibition and agrees with computational and experimental results previously reported in the literature. More resistant β-glucosidases are essential to saccharification in industrial applications. However, thermostable and glucose-tolerant β-glucosidases are rare, and their glucose tolerance mechanisms appear to be related to multiple and complex factors. We gather here, a set of information, and made predictions aiming to provide a tool for supporting the rational design of more efficient β-glucosidases. We hope that Glutantβase can help improve second-generation biofuel production. Glutantβase is available at http://bioinfo.dcc.ufmg.br/glutantbase .
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Affiliation(s)
- Diego Mariano
- Laboratory of Bioinformatics and Systems. Department of Computer Science, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, Brazil.
| | - Naiara Pantuza
- Laboratory of Bioinformatics and Systems. Department of Computer Science, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, Brazil
| | - Lucianna H Santos
- Laboratory of Bioinformatics and Systems. Department of Computer Science, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, Brazil
| | - Rafael E O Rocha
- Laboratory of Bioinformatics and Systems. Department of Computer Science, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, Brazil
| | - Leonardo H F de Lima
- Laboratory of Molecular Modelling and Bioinformatics (LAMMB), Department of Physical and Biological Sciences, Universidade Federal de São João Del-Rei, Campus Sete Lagoas, Sete Lagoas, 35701-970, Brazil
| | - Lucas Bleicher
- Protein Computational Biology Laboratory, Department of Biochemistry and Immunology, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, Brazil
| | - Raquel Cardoso de Melo-Minardi
- Laboratory of Bioinformatics and Systems. Department of Computer Science, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, Brazil.
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16
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Bermejo PM, Raghavendran V, Gombert AK. Neither 1G nor 2G fuel ethanol: setting the ground for a sugarcane-based biorefinery using an iSUCCELL yeast platform. FEMS Yeast Res 2020; 20:5836716. [PMID: 32401320 DOI: 10.1093/femsyr/foaa027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 05/11/2020] [Indexed: 11/12/2022] Open
Abstract
First-generation (1G) fuel ethanol production in sugarcane-based biorefineries is an established economic enterprise in Brazil. Second-generation (2G) fuel ethanol from lignocellulosic materials, though extensively investigated, is currently facing severe difficulties to become economically viable. Some of the challenges inherent to these processes could be resolved by efficiently separating and partially hydrolysing the cellulosic fraction of the lignocellulosic materials into the disaccharide cellobiose. Here, we propose an alternative biorefinery, where the sucrose-rich stream from the 1G process is mixed with a cellobiose-rich stream in the fermentation step. The advantages of mixing are 3-fold: (i) decreased concentrations of metabolic inhibitors that are typically produced during pretreatment and hydrolysis of lignocellulosic materials; (ii) decreased cooling times after enzymatic hydrolysis prior to fermentation; and (iii) decreased availability of free glucose for contaminating microorganisms and undesired glucose repression effects. The iSUCCELL platform will be built upon the robust Saccharomyces cerevisiae strains currently present in 1G biorefineries, which offer competitive advantage in non-aseptic environments, and into which intracellular hydrolyses of sucrose and cellobiose will be engineered. It is expected that high yields of ethanol can be achieved in a process with cell recycling, lower contamination levels and decreased antibiotic use, when compared to current 2G technologies.
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Affiliation(s)
| | - Vijayendran Raghavendran
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
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17
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Ulaeto SB, Mathew GM, Pancrecious JK, Nair JB, Rajan TPD, Maiti KK, Pai BC. Biogenic Ag Nanoparticles from Neem Extract: Their Structural Evaluation and Antimicrobial Effects against Pseudomonas nitroreducens and Aspergillus unguis (NII 08123). ACS Biomater Sci Eng 2019; 6:235-245. [PMID: 33463216 DOI: 10.1021/acsbiomaterials.9b01257] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Silver nanocrystals have been successfully fabricated by the bioreduction route using the ethanolic extract of Azadirachta indica (neem) leaves as the reducing and capping agent without solvent interference. The silver nanocrystals were grown in a single-step method, without the influence of external energy or surfactants, and at room temperature. The nanoparticles were prepared from different ratios of silver ions to reducing agent molecules and were characterized by UV-vis spectroscopy and transmission electron microscopy (TEM). The nanoparticles were roughly spherical and polydispersed with diameters of less than 40 nm, as determined with high-resolution transmission electron microscopy (HRTEM). Fast Fourier transform (FFT) analysis and X-ray diffraction (XRD) analysis elucidated the crystalline nature of the nanoparticles. The presence of participating functional groups was determined with Fourier transform infrared (FTIR) spectroscopy. The synthesized silver nanoparticles were analyzed as a potential surface-enhanced Raman spectroscopy (SERS) substrate by incorporating rhodamine B as the Raman reporter molecule. The bioreduction process was monitored through SERS fingerprint, which was evaluated by the change in vibrational energies of metal-ligand bonds. It was possible to detect the SERS spectral pattern of the probe molecules on the Ag nanoparticles without the use of any aggregating agent. Thus, the formation of probable intra- and interparticle hot spots was attributed to evaporation-induced aggregation. Furthermore, stirring and precursor salt concentration influenced the kinetics involved in the fabrication process. The thermal stability of the lyophilized nanoparticles prepared from 0.1 M AgNO3 was evaluated with thermogravimetric analysis (TGA) and had a residual mass of 60% at 600 °C. X-ray photoelectron spectroscopy (XPS) studies were used to validate the compositional and chemical-state information. The biomass-capped silver nanoparticles provided antimicrobial activity by inhibiting the growth of Pseudomonas nitroreducens, a biofilm-forming bacterium, and the fungus, Aspergillus unguis (NII 08123).
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Affiliation(s)
- Sarah B Ulaeto
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India.,Department of Chemical Sciences, Rhema University, Aba, Abia State 450271, Nigeria
| | | | - Jerin K Pancrecious
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - Jyothi B Nair
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - T P D Rajan
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - Kaustabh K Maiti
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
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18
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Gao L, Xu Y, Song X, Li S, Xia C, Xu J, Qin Y, Liu G, Qu Y. Deletion of the middle region of the transcription factor ClrB in Penicillium oxalicum enables cellulase production in the presence of glucose. J Biol Chem 2019; 294:18685-18697. [PMID: 31659120 DOI: 10.1074/jbc.ra119.010863] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 10/21/2019] [Indexed: 11/06/2022] Open
Abstract
Enzymes that degrade lignocellulose to simple sugars are of great interest in research and for biotechnology because of their role in converting plant biomass to fuels and chemicals. The synthesis of cellulolytic enzymes in filamentous fungi is tightly regulated at the transcriptional level, with the transcriptional activator ClrB/CLR-2 playing a critical role in many species. In Penicillium oxalicum, clrB overexpression could not relieve the dependence of cellulase expression on cellulose as an inducer, suggesting that clrB is controlled post-transcriptionally. In this study, using a reporter gene system in yeast, we identified the C-terminal region of ClrB/CLR-2 as a transcriptional activation domain. Expression of clrBID , encoding a ClrB derivative in which the DNA-binding and transcriptional activation domains are fused together to remove the middle region, led to cellulase production in the absence of cellulose in P. oxalicum Strikingly, the clrBID -expressing strain produced cellulase on carbon sources that normally repress cellulase expression, including glucose and glycerol. Results from deletion of the carbon catabolite repressor gene creA in the clrBID -expressing strain suggested that the effect of clrBID is independent of CreA's repressive function. A similar modification of clrB in Aspergillus niger resulted in the production of a mannanase in glucose medium. Taken together, these results indicate that ClrB suppression under noninducing conditions involves its middle region, suggesting a potential strategy to engineer fungal strains for improved cellulase production on commonly used carbon sources.
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Affiliation(s)
- Liwei Gao
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Yanning Xu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Xin Song
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Shiying Li
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Chengqiang Xia
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Jiadi Xu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China; National Glycoengineering Research Center, Shandong University, Qingdao 266237, China
| | - Yuqi Qin
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China; National Glycoengineering Research Center, Shandong University, Qingdao 266237, China
| | - Guodong Liu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China; National Glycoengineering Research Center, Shandong University, Qingdao 266237, China.
| | - Yinbo Qu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China; National Glycoengineering Research Center, Shandong University, Qingdao 266237, China
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19
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Characterization of a glucose tolerant β-glucosidase from Aspergillus unguis with high potential as a blend-in for biomass hydrolyzing enzyme cocktails. Biotechnol Lett 2019; 41:1201-1211. [DOI: 10.1007/s10529-019-02724-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 08/17/2019] [Indexed: 12/18/2022]
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20
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Uhoraningoga A, Kinsella GK, Frias JM, Henehan GT, Ryan BJ. The Statistical Optimisation of Recombinant β-glucosidase Production through a Two-Stage, Multi-Model, Design of Experiments Approach. Bioengineering (Basel) 2019; 6:bioengineering6030061. [PMID: 31323833 PMCID: PMC6784099 DOI: 10.3390/bioengineering6030061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 07/06/2019] [Accepted: 07/16/2019] [Indexed: 12/17/2022] Open
Abstract
β-glucosidases are a class of enzyme that are widely distributed in the living world, with examples noted in plants, fungi, animals and bacteria. They offer both hydrolysis and synthesis capacity for a wide range of biotechnological processes. However, the availability of native, or the production of recombinant β-glucosidases, is currently a bottleneck in the widespread industrial application of this enzyme. In this present work, the production of recombinant β-glucosidase from Streptomyces griseus was optimised using a Design of Experiments strategy, comprising a two-stage, multi-model design. Three screening models were comparatively employed: Fractional Factorial, Plackett-Burman and Definitive Screening Design. Four variables (temperature, incubation time, tryptone, and OD600 nm) were experimentally identified as having statistically significant effects on the production of S.griseus recombinant β-glucosidase in E. coli BL21 (DE3). The four most influential variables were subsequently used to optimise recombinant β-glucosidase production, employing Central Composite Design under Response Surface Methodology. Optimal levels were identified as: OD600 nm, 0.55; temperature, 26 °C; incubation time, 12 h; and tryptone, 15 g/L. This yielded a 2.62-fold increase in recombinant β-glucosidase production, in comparison to the pre-optimised process. Affinity chromatography resulted in homogeneous, purified β-glucosidase that was characterised in terms of pH stability, metal ion compatibility and kinetic rates for p-nitrophenyl-β-D-glucopyranoside (pNPG) and cellobiose catalysis.
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Affiliation(s)
- Albert Uhoraningoga
- School of Food Science and Environmental Health, College of Sciences and Health, Technological University Dublin, Dublin D07 ADY7, Ireland
| | - Gemma K Kinsella
- School of Food Science and Environmental Health, College of Sciences and Health, Technological University Dublin, Dublin D07 ADY7, Ireland
| | - Jesus M Frias
- School of Food Science and Environmental Health, College of Sciences and Health, Technological University Dublin, Dublin D07 ADY7, Ireland
| | - Gary T Henehan
- School of Food Science and Environmental Health, College of Sciences and Health, Technological University Dublin, Dublin D07 ADY7, Ireland
| | - Barry J Ryan
- School of Food Science and Environmental Health, College of Sciences and Health, Technological University Dublin, Dublin D07 ADY7, Ireland.
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21
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Srivastava N, Rathour R, Jha S, Pandey K, Srivastava M, Thakur VK, Sengar RS, Gupta VK, Mazumder PB, Khan AF, Mishra PK. Microbial Beta Glucosidase Enzymes: Recent Advances in Biomass Conversation for Biofuels Application. Biomolecules 2019; 9:E220. [PMID: 31174354 PMCID: PMC6627771 DOI: 10.3390/biom9060220] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/28/2019] [Accepted: 05/28/2019] [Indexed: 01/10/2023] Open
Abstract
The biomass to biofuels production process is green, sustainable, and an advanced technique to resolve the current environmental issues generated from fossil fuels. The production of biofuels from biomass is an enzyme mediated process, wherein β-glucosidase (BGL) enzymes play a key role in biomass hydrolysis by producing monomeric sugars from cellulose-based oligosaccharides. However, the production and availability of these enzymes realize their major role to increase the overall production cost of biomass to biofuels production technology. Therefore, the present review is focused on evaluating the production and efficiency of β-glucosidase enzymes in the bioconversion of cellulosic biomass for biofuel production at an industrial scale, providing its mechanism and classification. The application of BGL enzymes in the biomass conversion process has been discussed along with the recent developments and existing issues. Moreover, the production and development of microbial BGL enzymes have been explained in detail, along with the recent advancements made in the field. Finally, current hurdles and future suggestions have been provided for the future developments. This review is likely to set a benchmark in the area of cost effective BGL enzyme production, specifically in the biorefinery area.
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Affiliation(s)
- Neha Srivastava
- Department of Chemical Engineering and Technology, IIT (BHU), Varanasi 221005, India.
| | - Rishabh Rathour
- Department of Bioengineering, Integral University, Lucknow 226026, India.
| | - Sonam Jha
- Department of Botany, Banaras Hindu University, Varanasi 221005, India.
| | - Karan Pandey
- Department of Chemical Engineering and Technology, IIT (BHU), Varanasi 221005, India.
| | - Manish Srivastava
- Department of Physics and Astrophysics, University of Delhi, Delhi 110007, India.
| | - Vijay Kumar Thakur
- Enhanced Composites and Structures Center, School of Aerospace, Transport and Manufacturing, Cranfield University, Bedfordshire MK43 0AL, UK.
| | - Rakesh Singh Sengar
- Department of Agriculture Biotechnology, College of Agriculture, Sardar Vallabhbhai Patel, University of Agriculture and Technology, Meerut 250110, U.P., India.
| | - Vijai K Gupta
- Department of Chemistry and Biotechnology, ERA Chair of Green Chemistry, Tallinn University of Technology, 12618 Tallinn, Estonia.
| | | | - Ahamad Faiz Khan
- Department of Bioengineering, Integral University, Lucknow 226026, India.
| | - Pradeep Kumar Mishra
- Department of Chemical Engineering and Technology, IIT (BHU), Varanasi 221005, India.
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22
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A Computational Method to Propose Mutations in Enzymes Based on Structural Signature Variation (SSV). Int J Mol Sci 2019; 20:ijms20020333. [PMID: 30650542 PMCID: PMC6359350 DOI: 10.3390/ijms20020333] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 12/29/2018] [Accepted: 01/06/2019] [Indexed: 11/26/2022] Open
Abstract
With the use of genetic engineering, modified and sometimes more efficient enzymes can be created for different purposes, including industrial applications. However, building modified enzymes depends on several in vitro experiments, which may result in the process being expensive and time-consuming. Therefore, computational approaches could reduce costs and accelerate the discovery of new technological products. In this study, we present a method, called structural signature variation (SSV), to propose mutations for improving enzymes’ activity. SSV uses the structural signature variation between target enzymes and template enzymes (obtained from the literature) to determine if randomly suggested mutations may provide some benefit for an enzyme, such as improvement of catalytic activity, half-life, and thermostability, or resistance to inhibition. To evaluate SSV, we carried out a case study that suggested mutations in β-glucosidases: Essential enzymes used in biofuel production that suffer inhibition by their product. We collected 27 mutations described in the literature, and manually classified them as beneficial or not. SSV was able to classify the mutations with values of 0.89 and 0.92 for precision and specificity, respectively. Then, we used SSV to propose mutations for Bgl1B, a low-performance β-glucosidase. We detected 15 mutations that could be beneficial. Three of these mutations (H228C, H228T, and H228V) have been related in the literature to the mechanism of glucose tolerance and stimulation in GH1 β-glucosidase. Hence, SSV was capable of detecting promising mutations, already validated by in vitro experiments, that improved the inhibition resistance of a β-glucosidase and, consequently, its catalytic activity. SSV might be useful for the engineering of enzymes used in biofuel production or other industrial applications.
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Salgado JCS, Meleiro LP, Carli S, Ward RJ. Glucose tolerant and glucose stimulated β-glucosidases - A review. BIORESOURCE TECHNOLOGY 2018; 267:704-713. [PMID: 30093225 DOI: 10.1016/j.biortech.2018.07.137] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 07/24/2018] [Accepted: 07/26/2018] [Indexed: 05/22/2023]
Abstract
The β-glucosidases (β-D-glucoside glucohydrolase, EC 3.2.1.21) hydrolyze glycosidic bonds of alkyl-, amino-, or aryl-β-D-glucosides, cyanogenic glucosides, disaccharides and short oligosaccharides and can also catalyze the synthesis of glycosyl-bonds between different molecules via transglycosylation. Due to their ubiquitous phylogenetic distribution, substrate diversity and ability to both hydrolyze and synthesize glycosidic bonds, the catalysis and regulation of β-glucosidases have been extensively studied. Many β-glucosidases are inhibited by the reaction product glucose, and reduced catalytic activity may limit the biotechnological and industrial applications of these enzymes and this has stimulated the search for β-glucosidases that maintain their activity at high glucose concentrations. Studies of many glucose tolerant enzymes have been reported and due to the ongoing interest in these enzymes, here it has been reviewed this accumulated body of knowledge which provides valuable insights as to the kinetics, structure, regulation and evolution of glucose tolerant and glucose stimulated β-glucosidases.
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Affiliation(s)
- José Carlos Santos Salgado
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Luana Parras Meleiro
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil.
| | - Sibeli Carli
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Richard John Ward
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
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24
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Enhancing enzyme-aided production of fermentable sugars from poplar pulp in the presence of non-ionic surfactants. Bioprocess Biosyst Eng 2018; 41:1133-1142. [PMID: 29700656 DOI: 10.1007/s00449-018-1942-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 04/18/2018] [Indexed: 12/31/2022]
Abstract
Addition of surfactants to enzymatic hydrolysis has been reported to enhance the hydrolytic potential of enzymes in the bioconversion of lignocellulosic biomass to fermentable sugars. The objective of this investigation was to evaluate the effects of four non-ionic surfactants (PEG4000, PEG8000, TitronX-100, and Tween80) on the efficiency of enzymatic hydrolysis of steam-pretreated poplar using a commercial cellulase preparation (Cellic® CTec2). Statistical discriminant analysis at four variable factors (surfactant type, surfactant concentration, hydrolysis time, and substrate consistency) revealed that enzymatic hydrolysis was significantly enhanced in the presence of PEG4000, with 19.2% increase in glucose yield over control without surfactant, whereas ANOVA test indicated substrate consistency and hydrolysis time as the most significant factors (P < 0.05). Hydrolysis of poplar pulp at 5% w/w pulp consistency with CTec2 in presence of 1% w/w PEG4000 produced the highest glucose yield of 58.5% after 96 h reaction time.
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25
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Characterization of a Thermophilic Monosaccharide Stimulated β-Glucosidase from Acidothermus cellulolyticus. Chem Res Chin Univ 2018. [DOI: 10.1007/s40242-018-7408-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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26
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Zang X, Liu M, Fan Y, Xu J, Xu X, Li H. The structural and functional contributions of β-glucosidase-producing microbial communities to cellulose degradation in composting. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:51. [PMID: 29492106 PMCID: PMC5828080 DOI: 10.1186/s13068-018-1045-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Accepted: 02/06/2018] [Indexed: 05/04/2023]
Abstract
BACKGROUND Compost habitats sustain a vast ensemble of microbes that engender the degradation of cellulose, which is an important part of global carbon cycle. β-Glucosidase is the rate-limiting enzyme of degradation of cellulose. Thus, analysis of regulation of β-glucosidase gene expression in composting is beneficial to a better understanding of cellulose degradation mechanism. Genetic diversity and expression of β-glucosidase-producing microbial communities, and relationships of cellulose degradation, metabolic products and the relative enzyme activity during natural composting and inoculated composting were evaluated. RESULTS Compared with natural composting, adding inoculation agent effectively improved the degradation of cellulose, and maintained high level of the carboxymethyl cellulose (CMCase) and β-glucosidase activities in thermophilic phase. Gene expression analysis showed that glycoside hydrolase family 1 (GH1) family of β-glucosidase genes contributed more to β-glucosidase activity in the later thermophilic phase in inoculated compost. In the cooling phase of natural compost, glycoside hydrolase family 3 (GH3) family of β-glucosidase genes contributed more to β-glucosidase activity. Intracellular β-glucosidase activity played a crucial role in the regulation of β-glucosidase gene expression, and upregulation or downregulation was also determined by extracellular concentration of glucose. At sufficiently high glucose concentrations, the functional microbial community in compost was altered, which may contribute to maintaining β-glucosidase activity despite the high glucose content. CONCLUSION This research provides an ecological functional map of microorganisms involved in carbon metabolism in cattle manure-rice straw composting. The performance of the functional microbial groups in the two composting treatments is different, which is related to the cellulase activity and cellulose degradation, respectively.
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Affiliation(s)
- Xiangyun Zang
- College of Resources and Environmental Sciences, Northeast Agricultural University, Harbin, 150030 China
| | - Meiting Liu
- College of Resources and Environmental Sciences, Northeast Agricultural University, Harbin, 150030 China
| | - Yihong Fan
- College of Resources and Environmental Sciences, Northeast Agricultural University, Harbin, 150030 China
| | - Jie Xu
- College of Resources and Environmental Sciences, Northeast Agricultural University, Harbin, 150030 China
| | - Xiuhong Xu
- College of Resources and Environmental Sciences, Northeast Agricultural University, Harbin, 150030 China
| | - Hongtao Li
- College of Resources and Environmental Sciences, Northeast Agricultural University, Harbin, 150030 China
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Kar B, Verma P, den Haan R, Sharma AK. Characterization of a recombinant thermostable β-glucosidase from Putranjiva roxburghii expressed in Saccharomyces cerevisiae and its use for efficient biomass conversion. Process Biochem 2017. [DOI: 10.1016/j.procbio.2017.08.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Madhavan A, Pandey A, Sukumaran RK. Expression system for heterologous protein expression in the filamentous fungus Aspergillus unguis. BIORESOURCE TECHNOLOGY 2017; 245:1334-1342. [PMID: 28578805 DOI: 10.1016/j.biortech.2017.05.140] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 05/19/2017] [Accepted: 05/21/2017] [Indexed: 06/07/2023]
Abstract
Heterologous protein expression in filamentous fungi is advantageous, especially in the context of large scale production of high volume low value recombinant proteins. However, such systems are rare and not available in public domain. A novel filamentous fungus - Aspergillus unguis NII 08123 was used as host for developing a protein expression system. An expression cassette was assembled using A. nidulans glyceraldehyde 3 phosphate dehydrogenase promoter (Pgapd), tryptophan synthase transcription terminator (TtrpC) and hygromycin resistance gene (hph) as selection marker. The enhanced green fluorescent protein (GFP) gene from Aequorea victoria was used as the model test protein for the evaluation of the expression system. The genetic transformation of this novel fungus was optimized through electroporation. Use of heterologous signal peptides resulted in high levels of secreted expression. The fungal host-expression system combination was tested successfully for the expression of the recombinant therapeutic protein-human interferon beta (HuIFNβ).
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Affiliation(s)
- Aravind Madhavan
- Microbial Processes and Technology Division, National Institute for Interdisciplinary Science and Technology, CSIR, Thiruvananthapuram 695 019, India
| | - Ashok Pandey
- Microbial Processes and Technology Division, National Institute for Interdisciplinary Science and Technology, CSIR, Thiruvananthapuram 695 019, India; Center of Innovative and Applied Bioprocessing, Mohali 160 071, Punjab, India
| | - Rajeev K Sukumaran
- Microbial Processes and Technology Division, National Institute for Interdisciplinary Science and Technology, CSIR, Thiruvananthapuram 695 019, India.
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Singhania RR, Patel AK, Pandey A, Ganansounou E. Genetic modification: A tool for enhancing beta-glucosidase production for biofuel application. BIORESOURCE TECHNOLOGY 2017; 245:1352-1361. [PMID: 28596076 DOI: 10.1016/j.biortech.2017.05.126] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 05/17/2017] [Accepted: 05/19/2017] [Indexed: 05/25/2023]
Abstract
Beta-glucosidase (BGL) is a rate-limiting enzyme for cellulose hydrolysis as it acts in the final step of lignocellulosic biomass conversion to convert cellobiose into glucose, the final end product. Most of the fungal strains used for cellulase production are deficient in BGL hence BGL is supplemented into cellulases to have an efficient biomass conversion. Genetic engineering has enabled strain modification to produce BGL optimally with desired properties to be employed for biofuel applications. It has been cloned either directly into the host strains lacking BGL or into another expression system, to be overexpressed so as to be blended into BGL deficient cellulases. In this article, role of genetic engineering to overcome BGL limitations in the cellulase cocktail and its significance for biofuel applications has been critically reviewed.
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Affiliation(s)
- Reeta Rani Singhania
- DBT-IOC Advanced Bio-Energy Research Centre, Indian Oil Corporation; R&D Centre, Sector-13, Faridabad 121007, India
| | - Anil Kumar Patel
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu 96822, HI, United States.
| | - Ashok Pandey
- Center of Innovative and Applied Bioprocessing, Sector 81, Knowledge City PO Manauli, SAS Nagar, Mohali 140306, Punjab, India
| | - Edgard Ganansounou
- Bioenergy and Energy Planning Research Group, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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Meleiro LP, Salgado JCS, Maldonado RF, Carli S, Moraes LAB, Ward RJ, Jorge JA, Furriel RPM. Engineering the GH1 β-glucosidase from Humicola insolens: Insights on the stimulation of activity by glucose and xylose. PLoS One 2017; 12:e0188254. [PMID: 29145480 PMCID: PMC5690678 DOI: 10.1371/journal.pone.0188254] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 11/05/2017] [Indexed: 12/31/2022] Open
Abstract
The activity of the GH1 β-glucosidase from Humicola insolens (Bglhi) against p-nitrophenyl-β-D-glucopyranoside (pNP-Glc) and cellobiose is enhanced 2-fold by glucose and/or xylose. Kinetic and transglycosylation data showed that hydrolysis is preferred in the absence of monosaccharides. Stimulation involves allosteric interactions, increased transglycosylation and competition of the substrate and monosaccharides for the -1 glycone and the +1/+2 aglycone binding sites. Protein directed evolution has been used to generate 6 mutants of Bglhi with altered stimulation patterns. All mutants contain one of three substitutions (N235S, D237V or H307Y) clustered around the +1/+2 aglycone binding sites. Two mutants with the H307Y substitution preferentially followed the transglycosylation route in the absence of xylose or glucose. The strong stimulation of their pNP-glucosidase and cellobiase activities was accompanied by increased transglycosylation and higher monosaccharide tolerance. The D237V mutation favoured hydrolysis over transglycosylation and the pNP-glucosidase activity, but not the cellobiase activity, was stimulated by xylose. The substitution N235S abolished the preference for hydrolysis or transglycosylation; the cellobiase, but not the pNP-glucosidase activity of the mutants was strongly inhibited by xylose. Both the D237V and N235S mutations lowered tolerance to the monosaccharides. These results provide evidence that the fine modulation of the activity of Bglhi and mutants by glucose and/or xylose is regulated by the relative affinities of the glycone and aglycone binding sites for the substrate and the free monosaccharides.
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Affiliation(s)
- Luana Parras Meleiro
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brasil
- * E-mail:
| | - José Carlos Santos Salgado
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brasil
| | - Raquel Fonseca Maldonado
- Instituto Federal de Educação, Ciência e Tecnologia de São Paulo, São José dos Campos, São Paulo, Brasil
| | - Sibeli Carli
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brasil
| | - Luiz Alberto Beraldo Moraes
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brasil
| | - Richard John Ward
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brasil
| | - João Atílio Jorge
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brasil
| | - Rosa Prazeres Melo Furriel
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brasil
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Heterologous expression and biochemical studies of a thermostable glucose tolerant β-glucosidase from Methylococcus capsulatus ( bath strain ). Int J Biol Macromol 2017; 102:805-812. [DOI: 10.1016/j.ijbiomac.2017.04.078] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 04/20/2017] [Accepted: 04/21/2017] [Indexed: 12/18/2022]
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Parisutham V, Chandran SP, Mukhopadhyay A, Lee SK, Keasling JD. Intracellular cellobiose metabolism and its applications in lignocellulose-based biorefineries. BIORESOURCE TECHNOLOGY 2017; 239:496-506. [PMID: 28535986 DOI: 10.1016/j.biortech.2017.05.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 04/27/2017] [Accepted: 05/01/2017] [Indexed: 05/28/2023]
Abstract
Complete hydrolysis of cellulose has been a key characteristic of biomass technology because of the limitation of industrial production hosts to use cellodextrin, the partial hydrolysis product of cellulose. Cellobiose, a β-1,4-linked glucose dimer, is a major cellodextrin of the enzymatic hydrolysis (via endoglucanase and exoglucanase) of cellulose. Conversion of cellobiose to glucose is executed by β-glucosidase. The complete extracellular hydrolysis of celluloses has several critical barriers in biomass technology. An alternative bioengineering strategy to make the bioprocessing less challenging is to engineer microbes with the abilities to hydrolyze and assimilate the cellulosic-hydrolysate cellodextrin. Microorganisms engineered to metabolize cellobiose rather than the monomeric glucose can provide several advantages for lignocellulose-based biorefineries. This review describes the recent advances and challenges in engineering efficient intracellular cellobiose metabolism in industrial hosts. This review also describes the limitations of and future prospectives in engineering intracellular cellobiose metabolism.
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Affiliation(s)
- Vinuselvi Parisutham
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Sathesh-Prabu Chandran
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Aindrila Mukhopadhyay
- Joint BioEnergy Institute, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Sung Kuk Lee
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea; School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea.
| | - Jay D Keasling
- Joint BioEnergy Institute, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Department of Chemical and Biomolecular Engineering & Department of Bioengineering, UC Berkeley, Berkeley, CA 94720, USA; Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, KogleAllé, DK2970 Hørsholm, Denmark; Synthetic Biology Engineering Research Center (Synberc), Berkeley, CA 94720, USA
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Zhang Z, Wang M, Gao R, Yu X, Chen G. Synergistic effect of thermostable β-glucosidase TN0602 and cellulase on cellulose hydrolysis. 3 Biotech 2017; 7:54. [PMID: 28444598 DOI: 10.1007/s13205-017-0672-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 02/27/2017] [Indexed: 01/22/2023] Open
Abstract
Thermophilic enzymes have many potential benefits in industrial production with increased flexibility related to process configurations. A thermostable β-glucosidase from Thermotoga naphthophila RUK-10 was found to possess catalytic activity for cellobiose hydrolysis with a high potential for application in biomass conversion. The aggregation of cellobiose often has an inhibitory effect on cellobiohydrolases and endoglucanases during cellulose hydrolysis. The presence of β-glucosidases has a significant effect on reducing inhibition from hydrolytic products by hydrolysing the intermedia cellobiose. In this study, β-glucosidase TN0602 exhibited a high tolerance to glucose and high thermostability even after a long incubation (>72 h). Additionally, supplementing β-glucosidase TN0602 with microcrystalline cellulose, untreated corn straw and steam-exploded corn straw hydrolysis reactions containing a commercial cellulase led to an increased conversion rate in released glucose compared to hydrolysis without the addition of β-glucosidase (15.82, 30.62 and 35.21%, respectively); the increase of conversion rates were 61.86, 93.50 and 94.55%. It was thus shown that an obvious synergistic effect exists between TN0602 and cellulases for cellulose hydrolysis, suggesting its potential as a component of enzymatic cocktails for the conversion of lignocellulosic biomass to other chemicals.
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34
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Obeng EM, Adam SNN, Budiman C, Ongkudon CM, Maas R, Jose J. Lignocellulases: a review of emerging and developing enzymes, systems, and practices. BIORESOUR BIOPROCESS 2017. [DOI: 10.1186/s40643-017-0146-8] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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35
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Increased yield of β-glucosidase-catalyzed hydrolysis reactions in the presence of betaine-type metabolite analog. Bioprocess Biosyst Eng 2016; 40:153-159. [PMID: 27655352 DOI: 10.1007/s00449-016-1684-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Accepted: 09/14/2016] [Indexed: 10/21/2022]
Abstract
β-Glucosidases (EC 3.2.1.21), abundant enzymes distributed in animals, plants and microorganism, has been generating lots of attentions for bioethanol production from cellulosic biomass. In this study, using three different origins of β-glucosidases, glucose productivity of β-glucosidase-catalyzed hydrolysis reactions in the presence of synthetic betaine-type metabolite analog (2-N,N,N-tri-n-butylammonium) acetate, was investigated. By the addition of the analog, the hydrolysis yields for all β-glucosidases was highly improved from 4-13 to 64-100 %. To understand the factors affecting on the yield enhancements, the kinetic parameters, inhibition constants of end-product and temporal stability of β-glucosidases were compared. As a result, enhancement of the yields is mainly related to the increase in the temporal stability of β-glucosidases in the presence of the analog. The present findings lead to not only improve the glucose productivity of β-glucosidase-catalyzed hydrolysis reaction toward bioethanol production but also apply to a new stabilization method for various unstable enzymes.
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Larue K, Melgar M, Martin VJJ. Directed evolution of a fungal β-glucosidase in Saccharomyces cerevisiae. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:52. [PMID: 26949413 PMCID: PMC4778352 DOI: 10.1186/s13068-016-0470-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 02/22/2016] [Indexed: 05/13/2023]
Abstract
BACKGROUND β-glucosidases (BGLs) catalyze the hydrolysis of soluble cellodextrins to glucose and are a critical component of cellulase systems. In order to engineer Saccharomyces cerevisiae for the production of ethanol from cellulosic biomass, a BGL tailored to industrial bioconversions is needed. RESULTS We applied a directed evolution strategy to a glycosyl hydrolase family 3 (GH3) BGL from Aspergillus niger (BGL1) by expressing a library of mutated bgl1 genes in S. cerevisiae and used a two-step functional screen to identify improved enzymes. Twelve BGL variants that supported growth of S. cerevisiae on cellobiose and showed increased activity on the synthetic substrate p-nitrophenyl-β-D-glucopyranoside were identified and characterized. By performing kinetic experiments, we found that a Tyr → Cys substitution at position 305 of BGL1 dramatically reduced transglycosidation activity that causes inhibition of the hydrolytic reaction at high substrate concentrations. Targeted mutagenesis demonstrated that the position 305 residue is critical in GH3 BGLs and likely determines the extent to which transglycosidation reactions occur. We also found that a substitution at Gln(140) reduced the inhibitory effect of glucose and could be combined with the Y305C substitution to produce a BGL with decreased sensitivity to both the product and substrate. Using the crystal structure of a GH3 BGL from A. aculeatus, we mapped a group of beneficial mutations to the β/α domain of the molecule and postulate that this region modulates activity through subunit interactions. Six BGL variants were identified with substitutions in the MFα pre-sequence that was used to mediate secretion of the protein. Substitutions at Pro(21) or Val(22) of the MFα pre-sequence could produce up to a twofold increase in supernatant hydrolase activity and provides evidence that expression and/or secretion was an additional factor limiting hydrolytic activity. CONCLUSIONS Using directed evolution on BGL1, we identified a key residue that controls hydrolytic and transglycosidation reactions in GH3 BGLs. We also found that several beneficial mutations could be combined and increased the hydrolytic activity for both synthetic and natural substrates.
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Affiliation(s)
- Kane Larue
- Department of Biology, Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke West, Montreal, QC H4B 1R6 Canada
| | - Mindy Melgar
- Department of Biology, Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke West, Montreal, QC H4B 1R6 Canada
| | - Vincent J. J. Martin
- Department of Biology, Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke West, Montreal, QC H4B 1R6 Canada
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Budihal SR, Agsar D, Patil SR. Enhanced production and application of acidothermophilic Streptomyces cellulase. BIORESOURCE TECHNOLOGY 2016; 200:706-712. [PMID: 26556405 DOI: 10.1016/j.biortech.2015.10.098] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 10/29/2015] [Accepted: 10/30/2015] [Indexed: 06/05/2023]
Abstract
An efficient cellulolytic and acidothermophilic actinobacterium was isolated from soil, adhered to decomposing tree bark and was identified as Streptomyces DSK59. Screening of synthetic media and the media components identified that, a medium based on starch casein minerals containing carboxy methyl cellulose (CMC) and beef extract (BE) could support enhanced cellulase production by the organism. CMC, BE, NaCl, temperature and pH were accounted as significant for cellulase production and these were optimized using a response surface central composite design (CCD). Optimization of cellulase production resulted in an enhancement of endoglucanase activity to 27IUml(-1). Acidothermophillic Streptomyces cellulase was found to be efficient for hydrolysis of pretreated sorghum stover and liberated 0.413gg(-1) of total reducing sugars which was higher than previously reported sugar yields obtained using fungal enzymes.
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Affiliation(s)
- Saikumar R Budihal
- A-DBT Research Laboratory, Department of Microbiology, Gulbarga University, Kalaburagi 585106, India
| | - Dayanand Agsar
- A-DBT Research Laboratory, Department of Microbiology, Gulbarga University, Kalaburagi 585106, India.
| | - Sarvamangala R Patil
- Department of Biotechnology, Vishweshwariah College of Applied Sciences, Kalaburagi 585103, India
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Song W, Han X, Qian Y, Liu G, Yao G, Zhong Y, Qu Y. Proteomic analysis of the biomass hydrolytic potentials of Penicillium oxalicum lignocellulolytic enzyme system. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:68. [PMID: 26997974 PMCID: PMC4797192 DOI: 10.1186/s13068-016-0477-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 03/02/2016] [Indexed: 05/08/2023]
Abstract
BACKGROUND The mining of high-performance enzyme systems is necessary to develop industrial lignocellulose bioconversion. Large amounts of cellulases and hemicellulases can be produced by Penicillium oxalicum. Hence, the enzyme system of this hypercellulolytic fungus should be elucidated to help design optimum enzyme systems for effective biomass hydrolysis. RESULTS The cellulolytic and xylanolytic activities of an SP enzyme system prepared from P. oxalicum JU-A10 were comparatively analyzed. Results indicated that the fungus possesses a complete cellulolytic-xylanolytic enzyme system. The cellobiohydrolase- and xylanase-specific activities of this system were higher than those of two other enzyme systems, i.e., ST from Trichoderma reesei SN1 and another commercial preparation Celluclast 1.5L. Delignified corncob residue (DCCR) could be hydrolyzed by SP to a greater extent than corncob residue (CCR). Beta-glucosidase (BG) supplemented in SP increased the ability of the system to hydrolyze DCCR and CCR, and resulted in a 64 % decrease in enzyme dosage with the same glucose yield. The behaviors of the enzyme components in the hydrolysis of CCR were further investigated by monitoring individual enzyme dynamics. The total protein concentrations and cellobiohydrolase (CBH), endoglucanase (EG), and filter paper activities in the supernatants significantly decreased during saccharification. These findings were more evident in SP than in the other enzyme systems. The comparative proteomic analysis of the enzyme systems revealed that both SP and ST were rich in carbohydrate-degrading enzymes and multiple non-hydrolytic proteins. A larger number of carbohydrate-binding modules 1 (CBM1) were also identified in SP than in ST. This difference might be linked to the greater adsorption to substrates and lower hydrolysis efficiency of SP enzymes than ST during lignocellulose saccharification, because CBM1 not only targets enzymes to insoluble cellulose but also leads to non-productive adsorption to lignin. CONCLUSIONS Penicillium oxalicum can be applied to the biorefinery of lignocellulosic biomass. Its ability to degrade lignocellulosic substrates could be further improved by modifying its enzyme system on the basis of enzyme activity measurement and proteomic analysis. The proposed strategy may also be applied to other lignocellulolytic enzyme systems to enhance their hydrolytic performances rationally.
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Affiliation(s)
- Wenxia Song
- />State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, No.27 Shanda South Road, Jinan, 250100 Shandong China
| | - Xiaolong Han
- />State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, No.27 Shanda South Road, Jinan, 250100 Shandong China
| | - Yuanchao Qian
- />State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, No.27 Shanda South Road, Jinan, 250100 Shandong China
| | - Guodong Liu
- />State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, No.27 Shanda South Road, Jinan, 250100 Shandong China
| | - Guangshan Yao
- />State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, No.27 Shanda South Road, Jinan, 250100 Shandong China
| | - Yaohua Zhong
- />State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, No.27 Shanda South Road, Jinan, 250100 Shandong China
| | - Yinbo Qu
- />State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, No.27 Shanda South Road, Jinan, 250100 Shandong China
- />National Glycoengineering Research Center, Shandong University, No.27 Shanda South Road, Jinan, 250100 Shandong China
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A Neurospora crassa ÿ-glucosidase with potential for lignocellulose hydrolysis shows strong glucose tolerance and stimulation by glucose and xylose. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.molcatb.2015.09.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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40
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Expression of novel glucose tolerant β-glucosidase on cell surface by Rhodotorula glutinis isolate. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2015. [DOI: 10.1016/j.bcab.2015.06.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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41
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Weiss PHE, Álvares ACM, Gomes AA, Miletti LC, Skoronski E, da Silva GF, de Freitas SM, Magalhães MLB. Beta glucosidase from Bacillus polymyxa is activated by glucose-6-phosphate. Arch Biochem Biophys 2015; 580:50-6. [PMID: 26116788 DOI: 10.1016/j.abb.2015.06.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 06/19/2015] [Accepted: 06/21/2015] [Indexed: 01/10/2023]
Abstract
Optimization of cellulose enzymatic hydrolysis is crucial for cost effective bioethanol production from lignocellulosic biomass. Enzymes involved in cellulose hydrolysis are often inhibited by their end-products, cellobiose and glucose. Efforts have been made to produce more efficient enzyme variants that are highly tolerant to product accumulation; however, further improvements are still necessary. Based on an alternative approach we initially investigated whether recently formed glucose could be phosphorylated into glucose-6-phosphate to circumvent glucose accumulation and avoid inhibition of beta-glucosidase from Bacillus polymyxa (BGLA). The kinetic properties and structural analysis of BGLA in the presence of glucose-6-phosphate (G6P) were investigated. Kinetic studies demonstrated that enzyme was not inhibited by G6P. In contrast, the presence of G6P activated the enzyme, prevented beta glucosidase feedback inhibition by glucose accumulation and improved protein stability. G6P binding was investigated by fluorescence quenching experiments and the respective association constant indicated high affinity binding of G6P to BGLA. Data reported here are of great impact for future design strategies for second-generation bioethanol production.
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Affiliation(s)
- Paulo H E Weiss
- Biochemistry Laboratory, Department of Food and Animal Production, Center of Agroveterinary Sciences, State University of Santa Catarina, Lages, Santa Catarina 88520-000, Brazil
| | - Alice C M Álvares
- Biophysics Laboratory, Department of Cellular Biology, University of Brasília, Brasília 70910-900, Brazil
| | - Anderson A Gomes
- Water Treatment Laboratory, Department of Environmental Engineering, Center of Agroveterinary Sciences, State University of Santa Catarina, Lages, Santa Catarina 88520-000, Brazil
| | - Luiz C Miletti
- Biochemistry Laboratory, Department of Food and Animal Production, Center of Agroveterinary Sciences, State University of Santa Catarina, Lages, Santa Catarina 88520-000, Brazil
| | - Everton Skoronski
- Water Treatment Laboratory, Department of Environmental Engineering, Center of Agroveterinary Sciences, State University of Santa Catarina, Lages, Santa Catarina 88520-000, Brazil
| | - Gustavo F da Silva
- Biochemistry Laboratory, Department of Food and Animal Production, Center of Agroveterinary Sciences, State University of Santa Catarina, Lages, Santa Catarina 88520-000, Brazil
| | - Sonia M de Freitas
- Biophysics Laboratory, Department of Cellular Biology, University of Brasília, Brasília 70910-900, Brazil
| | - Maria L B Magalhães
- Biochemistry Laboratory, Department of Food and Animal Production, Center of Agroveterinary Sciences, State University of Santa Catarina, Lages, Santa Catarina 88520-000, Brazil.
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42
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Yang F, Yang X, Li Z, Du C, Wang J, Li S. Overexpression and characterization of a glucose-tolerant β-glucosidase from T. aotearoense with high specific activity for cellobiose. Appl Microbiol Biotechnol 2015; 99:8903-15. [DOI: 10.1007/s00253-015-6619-9] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 04/07/2015] [Accepted: 04/10/2015] [Indexed: 12/20/2022]
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43
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Molecular cloning and expression of thermostable glucose-tolerant β-glucosidase of Penicillium funiculosum NCL1 in Pichia pastoris and its characterization. ACTA ACUST UNITED AC 2015; 42:553-65. [DOI: 10.1007/s10295-014-1549-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 11/14/2014] [Indexed: 11/26/2022]
Abstract
Abstract
A partial peptide sequence of β-glucosidase isoform (Bgl4) of Penicillium funiculosum NCL1 was identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The cDNA (bgl4) encoding Bgl4 protein was cloned from P. funiculosum NCL1 RNA by consensus RT-PCR. The bgl4 gene encoded 857 amino acids that contained catalytic domains specific for glycoside hydrolase family 3. The cDNA was over-expressed in Pichia pastoris KM71H and the recombinant protein (rBgl4) was purified with the specific activity of 1,354.3 U/mg. The rBgl4 was a glycoprotein with the molecular weight of ~130 kDa and showed optimal activity at pH 5.0 and 60 °C. The enzyme was thermo-tolerant up to 60 °C for 60 min. The rBgl4 was highly active on aryl substrates with β-glucosidic, β-xylosidic linkages and moderately active on cellobiose and salicin. It showed remarkably high substrate conversion rate of 3,332 and 2,083 μmol/min/mg with the substrates p-nitrophenyl β-glucoside and cellobiose respectively. In addition, the rBgl4 showed tolerance to glucose concentration up to 400 mM. It exhibited twofold increase in glucose yield when supplemented with crude cellulase of Trichoderma reesei Rut-C30 in cellulose hydrolysis. These results suggested that rBgl4 is a thermo- and glucose-tolerant β-glucosidase and is a potential supplement for commercial cellulase in cellulose hydrolysis and thereby assures profitability in bioethanol production.
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Matsumoto T, Shimada S, Hata Y, Tanaka T, Kondo A. Multi-functional glycoside hydrolase: Blon_0625 from Bifidobacterium longum subsp. infantis ATCC 15697. Enzyme Microb Technol 2014; 68:10-4. [PMID: 25435500 DOI: 10.1016/j.enzmictec.2014.10.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 10/14/2014] [Accepted: 10/14/2014] [Indexed: 10/24/2022]
Abstract
We here describe a unique β-D-glucosidase (BGL; Blon_0625) derived from Bifidobacterium longum subsp. infantis ATCC 15697. The Blon_0625 gene was expressed by recombinant Escherichia coli. Purified recombinant Blon_0625 retains hydrolyzing activity against both p-nitrophenyl-β-D-glucopyranoside (pNPG; 17.3±0.24Umg(-1)) and p-nitrophenyl-β-D-xylopyranoside (pNPX; 16.7±0.32Umg(-1)) at pH 6.0, 30°C. To best of our knowledge, no previously described BGL retains the same level of both pNPGase and pNPXase activity. Furthermore, Blon_0625 also retains the activity against 4-nitrophenyl-α-l-arabinofranoside (pNPAf; 5.6±0.09Umg(-1)). In addition, the results of the degradation of phosphoric acid swollen cellulose (PASC) or xylan using endoglucanase from Thermobifida fusca YX (Tfu_0901) or xylanase from Kitasatospora setae KM-6054 (KSE_59480) show that Blon_0625 acts as a BGL and as a β-D-xylosidase (XYL) for hydrolyzing oligosaccharides. These results clearly indicate that Blon_0625 is a multi-functional glycoside hydrolase which retains the activity of BGL, XYL, and also α-l-arabinofuranosidase. Therefore, the utilization of multi-functional Blon_0625 may contribute to facilitating the efficient degradation of lignocellulosic materials and help enhance bioconversion processes.
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Affiliation(s)
- Takuya Matsumoto
- Organization of Advanced Science and Technology, Kobe University, 1-1 Rokkodaicho, Nada, Kobe 657-8501, Japan
| | - Shota Shimada
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodaicho, Nada, Kobe 657-8501, Japan
| | - Yuto Hata
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodaicho, Nada, Kobe 657-8501, Japan
| | - Tsutomu Tanaka
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodaicho, Nada, Kobe 657-8501, Japan.
| | - Akihiko Kondo
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodaicho, Nada, Kobe 657-8501, Japan
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Wu P, Zhao X, Pan S. Intraspecific protoplast fusion of Brettanomyces anomalus for improved production of an extracellular β-glucosidase. BIOTECHNOL BIOTEC EQ 2014; 28:878-881. [PMID: 26019572 PMCID: PMC4434049 DOI: 10.1080/13102818.2014.955290] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2014] [Accepted: 04/16/2014] [Indexed: 10/28/2022] Open
Abstract
Improvement of production of an extracellular β-glucosidase with high activity by Brettanomyces anomalus PSY-001 was performed by using recursive protoplast fusion in a genome-shuffling format. The initial population was generated by ultraviolet irradiation, ultrasonic mutagenesis and, then, subjected to recursive protoplast fusion. Mutant strains exhibiting significantly higher β-glucosidase activities in liquid media were isolated. The best mutant strain showed increased cell growth in a flask culture, as well as increased β-glucosidase production. A recombinant strain, F3-25, was obtained after three rounds of genome shuffling and its production of β-glucosidase activity reached 4790 U L-1, which was a nearly eightfold increase compared to the original strain B. anomalus PSY-001. The subculture experiments indicated that F3-25 was genetically stable.
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Affiliation(s)
- Peng Wu
- Hubei Key Laboratory of Economic Forest Germplasm Improvement and Resources Comprehensive Utilization, College of Life Sciences, Huanggang Normal University, Huanggang, Hubei, P. R. China
| | - Xihong Zhao
- Key Laboratory for Green Chemical Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan, Hubei, P. R. China
| | - Siyi Pan
- Key Laboratory of Environment Correlative Dietology, Ministry of Education, College of Food Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, P. R. China
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Gao L, Gao F, Jiang X, Zhang C, Zhang D, Wang L, Wu G, Chen S. Biochemical characterization of a new β-glucosidase (Cel3E) from Penicillium piceum and its application in boosting lignocelluloses bioconversion and forming disaccharide inducers: New insights into the role of β-glucosidase. Process Biochem 2014. [DOI: 10.1016/j.procbio.2014.02.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Biver S, Stroobants A, Portetelle D, Vandenbol M. Two promising alkaline β-glucosidases isolated by functional metagenomics from agricultural soil, including one showing high tolerance towards harsh detergents, oxidants and glucose. ACTA ACUST UNITED AC 2014; 41:479-88. [DOI: 10.1007/s10295-014-1400-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 01/01/2014] [Indexed: 01/07/2023]
Abstract
Abstract
New β-glucosidase activities were identified by screening metagenomic libraries constructed with DNA isolated from the topsoil of a winter wheat field. Two of the corresponding proteins, displaying an unusual preference for alkaline conditions, were selected for purification by Ni-NTA chromatography. AS-Esc6, a 762-amino-acid enzyme belonging to glycoside hydrolase family 3, proved to be a mesophilic aryl-β-glucosidase with maximal activity around pH 8 and 40 °C. A similar pH optimum was found for AS-Esc10, a 475-amino-acid GH1-family enzyme, but this enzyme remained significantly active across a wider pH range and was also markedly more stable than AS-Esc6 at pH greater than 10. AS-Esc10 was found to degrade cellobiose and diverse aryl glycosides, with an optimal temperature of 60 °C and good stability up to 50 °C. Unlike AS-Esc6, which showed a classically low inhibitory constant for glucose (14 mM), AS-Esc10 showed enhanced activity in the presence of molar concentrations of glucose. AS-Esc10 was highly tolerant to hydrogen peroxide and also to sodium dodecyl sulfate, this being indicative of kinetic stability. This unique combination of properties makes AS-Esc10 a particularly promising candidate whose potential in biotechnological applications is worth exploring further.
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Affiliation(s)
- Sophie Biver
- grid.4861.b 0000000108057253 Microbiology and Genomics Unit, Gembloux Agro-Bio Tech University of Liège Avenue Maréchal Juin 6 5030 Gembloux Belgium
| | - Aurore Stroobants
- grid.4861.b 0000000108057253 Microbiology and Genomics Unit, Gembloux Agro-Bio Tech University of Liège Avenue Maréchal Juin 6 5030 Gembloux Belgium
| | - Daniel Portetelle
- grid.4861.b 0000000108057253 Microbiology and Genomics Unit, Gembloux Agro-Bio Tech University of Liège Avenue Maréchal Juin 6 5030 Gembloux Belgium
| | - Micheline Vandenbol
- grid.4861.b 0000000108057253 Microbiology and Genomics Unit, Gembloux Agro-Bio Tech University of Liège Avenue Maréchal Juin 6 5030 Gembloux Belgium
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Gao L, Gao F, Zhang D, Zhang C, Wu G, Chen S. Purification and characterization of a new β-glucosidase from Penicillium piceum and its application in enzymatic degradation of delignified corn stover. BIORESOURCE TECHNOLOGY 2013; 147:658-661. [PMID: 24025854 DOI: 10.1016/j.biortech.2013.08.089] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 08/13/2013] [Accepted: 08/14/2013] [Indexed: 05/07/2023]
Abstract
A new β-glucosidase (Cel3B) was first isolated from cellulytic fungi, designated as PpCel3B. Although PpCel3B was classified to GH family 3 based on the homology sequence, PpCel3B had different biological functions in cellulose degradation and signaling molecules production. PpCel3B was constitutive and could form multiple soluble lignocellulose inducers for cellulase and hemicellulase synthesis via high tranglycosylation activity and new enzymatic activity. Moreover, PpCel3B showed apparent synergism with cellulases by removing several inhibitors. Supplementing low doses of PpCel3B (52 μg/g substrate) increased saccharification efficiency of cellulase produced by Trichoderma reesei and Penicillium piceum by 15% and 35%, respectively on delignified corn stover. PpCel3B had important application in boosting cellulase yield and efficiency.
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Affiliation(s)
- Le Gao
- Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Feng Gao
- Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Dongyuan Zhang
- Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Can Zhang
- Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Gaihong Wu
- Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Shulin Chen
- Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.
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