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de Camargo BR, Takematsu HM, Ticona ARP, da Silva LA, Silva FL, Quirino BF, Hamann PRV, Noronha EF. Penicillium polonicum a new isolate obtained from Cerrado soil as a source of carbohydrate-active enzymes produced in response to sugarcane bagasse. 3 Biotech 2022; 12:348. [PMID: 36386566 PMCID: PMC9652181 DOI: 10.1007/s13205-022-03405-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 09/30/2022] [Indexed: 11/13/2022] Open
Abstract
Penicillium species have been studied as producers of plant cell wall degrading enzymes to deconstruct agricultural residues and to be applied in industrial processes. Natural environments containing decaying plant matter are ideal places for isolating fungal strains with cellulolytic and xylanolytic activities. In the present study, Cerrado soil samples were used as source of filamentous fungi able to degrade xylan and cellulose. Penicillium was the most abundant genus among the obtained xylan and carboxymethylcellulose degraders. Penicillium polonicum was one of the best enzyme producers in agar-plate assays. In addition, it secretes CMCase, Avicelase, pectinase, mannanase, and xylanase during growth in liquid media containing sugarcane bagasse as carbon source. The highest value for endo-β-1,4-xylanase activity was obtained after 4 days of growth. Xyl PP, a 20 kDa endo-β-1,4-xylanase, was purified and partially characterized. The purified enzyme presented the remarkable feature of being resistant to the lignin-derived phenolic compounds, p-coumaric and trans-ferulic acids. This feature calls for its further use in bioprocesses that use lignocellulose as feedstock. Furthermore, future work should explore its structural features which may contribute to the understanding of the relationship between its structure and resistance to phenolic compounds. Supplementary Information The online version contains supplementary material available at 10.1007/s13205-022-03405-x.
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Affiliation(s)
- Brenda Rabelo de Camargo
- Department of Cell Biology, Institute of Biological Sciences, University of Brasilia, Brasilia, DF 70910-900 Brazil
| | - Hamille Mey Takematsu
- Department of Cell Biology, Institute of Biological Sciences, University of Brasilia, Brasilia, DF 70910-900 Brazil
| | - Alonso R. Poma Ticona
- Department of Cell Biology, Institute of Biological Sciences, University of Brasilia, Brasilia, DF 70910-900 Brazil
| | - Leonardo Assis da Silva
- Department of Cell Biology, Institute of Biological Sciences, University of Brasilia, Brasilia, DF 70910-900 Brazil
| | - Francilene Lopes Silva
- Department of Cell Biology, Institute of Biological Sciences, University of Brasilia, Brasilia, DF 70910-900 Brazil
| | - Betania Ferraz Quirino
- Embrapa-Agroenergia, Genetics and Biotechnology Laboratory, Brasilia, DF 70770-901 Brazil
| | - Pedro R. Vieira Hamann
- Department of Cell Biology, Institute of Biological Sciences, University of Brasilia, Brasilia, DF 70910-900 Brazil
| | - Eliane Ferreira Noronha
- Department of Cell Biology, Institute of Biological Sciences, University of Brasilia, Brasilia, DF 70910-900 Brazil
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Rabee AE, Younan BR, Kewan KZ, Sabra EA, Lamara M. Modulation of rumen bacterial community and feed utilization in camel and sheep using combined supplementation of live yeast and microalgae. Sci Rep 2022; 12:12990. [PMID: 35906456 PMCID: PMC9338284 DOI: 10.1038/s41598-022-16988-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 07/19/2022] [Indexed: 11/17/2022] Open
Abstract
The combination of live yeast and microalgae as feed supplementation could improve rumen fermentation and animal productivity. This study aimed to investigate the impact of a mixture of (YA) yeast (Saccharomyces cerevisiae) and microalgae (Spirulina platensis and Chlorella vulgaris) as feed supplementation on feed intake, rumen disappearance of barley straw, bacteria, and fermentation, blood parameters of camels and sheep. Three fistulated camels and three fistulated rams were fed a concentrates mixture and ad libitum barley straw as a basal diet alone or supplemented with YA mixture. The dietary supplementation improved the feed intake, rumen disappearance of barley straw nutrients, and the blood immunity parameters. The YA supplementation affected rumen fermentation as well as the composition and diversity of rumen bacteria; however, the response to the supplementation varied according to animal species. Principle Coordinate Analysis (PCoA) separated bacterial communities based on animal species and feeding treatment. Phylum Bacteroidetes and Firmicutes dominated the bacterial community; and the dominant genera were Prevotella, RC9_gut_group, Butyrivibrio, Ruminococcus, Saccharofermentans, Christensenellaceae_R-7_group, and Succiniclasticum. Our results suggest positive impacts of YA supplementation in rumen fermentation and animal performance.
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Affiliation(s)
- Alaa Emara Rabee
- Animal and Poultry Nutrition Department, Desert Research Center, Cairo, Egypt.
| | - Boshra R Younan
- Animal and Poultry Nutrition Department, Desert Research Center, Cairo, Egypt
| | - Khalid Z Kewan
- Animal and Poultry Nutrition Department, Desert Research Center, Cairo, Egypt
| | - Ebrahim A Sabra
- Genetic Engineering and Biotechnology Research Institute, University of Sadat City, Sadat City, Egypt
| | - Mebarek Lamara
- Forest Research Institute, University of Quebec in Abitibi-Temiscamingue, Rouyn-Noranda, Canada
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Preparation and characterization of sugilite glass from basalt for α -amylase immobilization, statistical optimization of the immobilization process and description of free and immobilized enzyme. Heliyon 2022; 8:e09960. [PMID: 35874060 PMCID: PMC9305367 DOI: 10.1016/j.heliyon.2022.e09960] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Revised: 05/31/2022] [Accepted: 07/12/2022] [Indexed: 11/23/2022] Open
Abstract
Bacterial α-amylase was immobilized on sugilite from modified basalt rock as a new carrier. A set of glass compositions based on sugilite formula KNa2M2Li3Si12O30 (M = Al or Mn or Fe) were prepared. The glasses were prepared through melting–quenching technique and samples of glass were converted to glass ceramic. Among the tested glasses and glass ceramic only sugilite glass based on M = Fe (BSF) give promising results. The sugilite BSF glass was characterized using DSC analysis, FTIR absorption, and SEM. The sugilite glass revealed high thermal resistant till ∼770 °C. Under optimized conditions of the Central composite design, the immobilization yield improved by 4.7-fold. The affinity to starch increased after enzyme immobilization by 4.3-fold. The lower rate of deactivation constant and the increase of t½ and D-value confirm the suitability of BSF and immobilization method in enhancing enzyme stability. The improvement in thermostability of immobilized α-amylase was judged by the change in thermodynamic parameters. In conclusion, the prepared sugilite BSF glass can be utilized as a new carrier suitable for stabilization of α-amylase enzyme by immobilization. Lemon peels induced α-amylase production by isolated Rhizobium sp. strain A1. Using basalt as raw material for sugilite glass synthesis as new immobilization carriers. Sugilite BSF glass the suitable carrier was characterized by DSC, FTIR and SEM. Central composite design increased immobilization yield by 4.7–fold. Thermal and thermodynamic properties emphasize increased stability upon immobilization.
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Rabee AE, Sayed Alahl AA, Lamara M, Ishaq SL. Fibrolytic rumen bacteria of camel and sheep and their applications in the bioconversion of barley straw to soluble sugars for biofuel production. PLoS One 2022; 17:e0262304. [PMID: 34995335 PMCID: PMC8740978 DOI: 10.1371/journal.pone.0262304] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 12/21/2021] [Indexed: 01/04/2023] Open
Abstract
Lignocellulosic biomass such as barley straw is a renewable and sustainable alternative to traditional feeds and could be used as bioenergy sources; however, low hydrolysis rate reduces the fermentation efficiency. Understanding the degradation and colonization of barley straw by rumen bacteria is the key step to improve the utilization of barley straw in animal feeding or biofuel production. This study evaluated the hydrolysis of barley straw as a result of the inoculation by rumen fluid of camel and sheep. Ground barley straw was incubated anaerobically with rumen inocula from three fistulated camels (FC) and three fistulated sheep (FR) for a period of 72 h. The source of rumen inoculum did not affect the disappearance of dry matter (DMD), neutral detergent fiber (NDFD). Group FR showed higher production of glucose, xylose, and gas; while higher ethanol production was associated with cellulosic hydrolysates obtained from FC group. The diversity and structure of bacterial communities attached to barley straw was investigated by Illumina Mi-Seq sequencing of V4-V5 region of 16S rRNA genes. The bacterial community was dominated by phylum Firmicutes and Bacteroidetes. The dominant genera were RC9_gut_group, Ruminococcus, Saccharofermentans, Butyrivibrio, Succiniclasticum, Selenomonas, and Streptococcus, indicating the important role of these genera in lignocellulose fermentation in the rumen. Group FR showed higher RC9_gut_group and group FC revealed higher Ruminococcus, Saccharofermentans, and Butyrivibrio. Higher enzymes activities (cellulase and xylanase) were associated with group FC. Thus, bacterial communities in camel and sheep have a great potential to improve the utilization lignocellulosic material in animal feeding and the production of biofuel and enzymes.
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Affiliation(s)
- Alaa Emara Rabee
- Animal and Poultry Nutrition Department, Desert Research Center, Cairo, Egypt
| | | | - Mebarek Lamara
- Forest Research Institute, University of Quebec in Abitibi-Temiscamingue, Rouyn-Noranda, Canada
| | - Suzanne L. Ishaq
- School of Food and Agriculture, University of Maine, Orono, Maine, United States of America
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Rabee AE. Effect of barley straw and Egyptian clover hay on the rumen fermentation and structure and fibrolytic activities of rumen bacteria in dromedary camel. Vet World 2022; 15:35-45. [PMID: 35369587 PMCID: PMC8924375 DOI: 10.14202/vetworld.2022.35-45] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 12/17/2021] [Indexed: 01/04/2023] Open
Abstract
Background and Aim Understanding the regulations of rumen microbiota and their fibrolytic capabilities under different forages are essential to improve rumen fermentation and animal feed efficiency. This study aimed to evaluate the changes in the rumen fermentation and the structure and fibrolytic activities of rumen bacteria in camels fed barley straw and Egyptian clover hay. Materials and Methods Three fistulated camels were fed a diet containing barley straw for 30 days; then transitioned to a diet containing Egyptian clover hay for 30 days. In addition, bacterial media enriched with xylan and different cellulose sources, namely, filter paper, wheat straw, and alfalfa hay, were used to evaluate the ability of camel rumen bacteria to produce xylanase and cellulase enzymes. Results The camel group fed Egyptian clover hay showed higher crude protein intake, rumen ammonia, total volatile fatty acids, and acetic acid. Moreover, the camel group fed barley straw showed higher neutral detergent fiber intake, rumen pH, and propionic and butyric acids. Principal component analysis showed that bacterial communities were separated based on the forage type. Forage type affected the composition of rumen bacteria and most of the bacterial community was assigned to phylum Bacteroidetes and Firmicutes. Egyptian clover hay diet increased the proportions of genus Prevotella and Ruminococcus; while fed barley straw diet increased the Butyrivibrio, RC9_gut_group, and Fibrobacteres. The bacterial culture of the Egyptian clover hay fed group produced the greatest xylanase and the bacterial culture of the barley straw fed group produced the maximum cellulase. Conclusion Egyptian clover hay is recommended to feed camels in intensive production. Moreover, the bacterial community in the camel rumen is a promising source of lignocellulolytic enzymes.
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Affiliation(s)
- Alaa Emara Rabee
- Department of Animal and Poultry Nutrition, Desert Research Center, Cairo, Egypt
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Antonopoulou G. Designing Efficient Processes for Sustainable Bioethanol and Bio-Hydrogen Production from Grass Lawn Waste. Molecules 2020; 25:molecules25122889. [PMID: 32586042 PMCID: PMC7355486 DOI: 10.3390/molecules25122889] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 06/20/2020] [Accepted: 06/21/2020] [Indexed: 12/04/2022] Open
Abstract
The effect of thermal, acid and alkali pretreatment methods on biological hydrogen (BHP) and bioethanol production (BP) from grass lawn (GL) waste was investigated, under different process schemes. BHP from the whole pretreatment slurry of GL was performed through mixed microbial cultures in simultaneous saccharification and fermentation (SSF) mode, while BP was carried out through the C5yeast Pichia stipitis, in SSF mode. From these experiments, the best pretreatment conditions were determined and the efficiencies for each process were assessed and compared, when using either the whole pretreatment slurry or the separated fractions (solid and liquid), the separate hydrolysis and fermentation (SHF) or SSF mode, and especially for BP, the use of other yeasts such as Pachysolen tannophilus or Saccharomyces cerevisiae. The experimental results showed that pretreatment with 10 gH2SO4/100 g total solids (TS) was the optimum for both BHP and BP. Separation of solid and liquid pretreated fractions led to the highest BHP (270.1 mL H2/g TS, corresponding to 3.4 MJ/kg TS) and also BP (108.8 mg ethanol/g TS, corresponding to 2.9 MJ/kg TS) yields. The latter was achieved by using P. stipitis for the fermentation of the hydrolysate and S. serevisiae for the solid fraction fermentation, at SSF.
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Affiliation(s)
- Georgia Antonopoulou
- Institute of Chemical Engineering Sciences, Stadiou, Platani, 26504 Patras, Greece
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Carrillo-Nieves D, Rostro Alanís MJ, de la Cruz Quiroz R, Ruiz HA, Iqbal HM, Parra-Saldívar R. Current status and future trends of bioethanol production from agro-industrial wastes in Mexico. RENEWABLE & SUSTAINABLE ENERGY REVIEWS 2019. [DOI: 10.1016/j.rser.2018.11.031] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Nisha M, Saranyah K, Shankar M, Saleena LM. Enhanced saccharification of lignocellulosic agricultural biomass and increased bioethanol titre using acclimated Clostridium thermocellum DSM1313. 3 Biotech 2017; 7:35. [PMID: 28409424 PMCID: PMC5391369 DOI: 10.1007/s13205-017-0606-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 01/07/2017] [Indexed: 12/29/2022] Open
Abstract
Consolidated bioprocess assures an efficient lignocellulosic conversion to fermentable sugars and subsequently to bioethanol. Such a single-step hydrolysis and anaerobic fermentation was achieved with acclimated Clostridium thermocellum DSM 1313 on different mildly pre-treated agricultural lignocellulosic residues without any additional enzymes/and strains. Acclimation was achieved by serially sub-culturing in increasing concentration of individual substrates, such as rice husk, sugarcane bagasse, and banana pseudostem in the standard media, with cellobiose as an adjunct. The acclimated cellulolytic thermophile exhibited an early log phase entry with enhanced growth compared to the direct inoculation experiments with unacclimated culture. Around 672 mg/g of reducing sugar was produced from sugarcane bagasse media and 636 mg/g from rice husk media and 513 mg/g from banana pseudostem media with the acclimated organism. Bioethanol production also doubled in experiments with serially acclimated cultures, with a maximum of 1.21 and 1.0 g/L ethanol titre from sugarcane bagasse and rice husk, respectively. The serial acclimation experiments have increased the saccharification potentials of the organism towards the respective lignocellulosic substrates and also enhanced the bioethanol production.
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Affiliation(s)
- M. Nisha
- Department of Biotechnology, School of Bioengineering, SRM University, Kattankulathur, Chennai, Tamil Nadu 603203 India
| | - K. Saranyah
- Department of Biotechnology, School of Bioengineering, SRM University, Kattankulathur, Chennai, Tamil Nadu 603203 India
| | - Mukund Shankar
- Department of Chemical Engineering, School of Bioengineering, SRM University, Kattankulathur, Chennai, Tamil Nadu 603203 India
| | - L. M. Saleena
- Department of Biotechnology, School of Bioengineering, SRM University, Kattankulathur, Chennai, Tamil Nadu 603203 India
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Osiro KO, de Camargo BR, Satomi R, Hamann PRV, Silva JP, de Sousa MV, Quirino BF, Aquino EN, Felix CR, Murad AM, Noronha EF. Characterization of Clostridium thermocellum (B8) secretome and purified cellulosomes for lignocellulosic biomass degradation. Enzyme Microb Technol 2017; 97:43-54. [DOI: 10.1016/j.enzmictec.2016.11.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Revised: 11/04/2016] [Accepted: 11/05/2016] [Indexed: 11/16/2022]
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Singh S, Moholkar VS, Goyal A. Optimization of carboxymethylcellulase production from Bacillus amyloliquefaciens SS35. 3 Biotech 2014; 4:411-424. [PMID: 28324477 PMCID: PMC4145630 DOI: 10.1007/s13205-013-0169-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2013] [Accepted: 08/26/2013] [Indexed: 11/21/2022] Open
Abstract
In this paper, we have attempted optimization of production of enzyme carboxymethylcellulase or endoglucanase from the bacterium Bacillus amyloliquefaciens SS35. Optimization has been carried out in two stages using statistical experimental design, viz. medium optimization and optimization of fermentation parameters. For medium optimization, Plackett–Burman design followed by central composite design (CCD) was used, while for optimization of fermentation parameters one-variable-at-a-time method followed by CCD was used. Carbon and nitrogen sources in the medium have been revealed to be the significant factors for enzyme production (carboxymethylcellulose 18.05 g/L; yeast extract 8 g/L and peptone 2 g/L). The inorganic salts have been found to be insignificant components of medium. Optimum fermentation parameters for optimized medium were: initial medium pH 5.65, incubation temperature = 40 °C, shaking speed = 120 rpm, and inoculum size = 6.96 %, v/v. Interestingly, the influence of all four parameters was almost independent with no interlinks. Secondly, the overall effect of all parameters was also low, as indicated by linear, square and interaction regression coefficients that were at least one order of magnitude lower than the intercept in the model equation. These results essentially meant that medium components dominate overall enzyme production process in comparison to fermentation parameters.
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Genetically modified Saccharomyces cerevisiae for one-step fermentation of bioalcohol using corncob as sole carbon source. ANN MICROBIOL 2014. [DOI: 10.1007/s13213-013-0714-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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Das SP, Ravindran R, Deka D, Jawed M, Das D, Goyal A. Bioethanol production from leafy biomass of mango (Mangifera indica) involving naturally isolated and recombinant enzymes. Prep Biochem Biotechnol 2014; 43:717-34. [PMID: 23768115 DOI: 10.1080/10826068.2013.773342] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The present study describes the usage of dried leafy biomass of mango (Mangifera indica) containing 26.3% (w/w) cellulose, 54.4% (w/w) hemicellulose, and 16.9% (w/w) lignin, as a substrate for bioethanol production from Zymomonas mobilis and Candida shehatae. The substrate was subjected to two different pretreatment strategies, namely, wet oxidation and an organosolv process. An ethanol concentration (1.21 g/L) was obtained with Z. mobilis in a shake-flask simultaneous saccharification and fermentation (SSF) trial using 1% (w/v) wet oxidation pretreated mango leaves along with mixed enzymatic consortium of Bacillus subtilis cellulase and recombinant hemicellulase (GH43), whereas C. shehatae gave a slightly higher (8%) ethanol titer of 1.31 g/L. Employing 1% (w/v) organosolv pretreated mango leaves and using Z. mobilis and C. shehatae separately in the SSF, the ethanol titers of 1.33 g/L and 1.52 g/L, respectively, were obtained. The SSF experiments performed with 5% (w/v) organosolv-pretreated substrate along with C. shehatae as fermentative organism gave a significantly enhanced ethanol titer value of 8.11 g/L using the shake flask and 12.33 g/L at the bioreactor level. From the bioreactor, 94.4% (v/v) ethanol was recovered by rotary evaporator with 21% purification efficiency.
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Affiliation(s)
- Saprativ P Das
- Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati, Assam, India
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Statistical Optimization of Fermentation Process Parameters by Taguchi Orthogonal Array Design for Improved Bioethanol Production. ACTA ACUST UNITED AC 2014. [DOI: 10.1155/2014/419674] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The statistical optimization of different fermentation process parameters in SSF of mixed MAA and organosolv pretreated 1% (w v−1) wild grass, namely, recombinant Clostridium thermocellum hydrolytic enzymes’ volume (GH5 cellulase, GH43 hemicellulase), fermentative microbes’ inoculum volume (Saccharomyces cerevisiae, Candida shehatae), pH, and temperature, was accomplished by Taguchi orthogonal array design. The optimized parameters in 100 mL of fermentation medium were (%, v v−1) as follows: 1.0, recombinant GH5 cellulase (5.7 mg−1, 0.45 mg mL−1); 2.0, recombinant GH43 hemicellulase (3.7 U mg−1, 0.32 mg mL−1); 1.5, S. cerevisiae (3.9 × 108 cells mL−1); 0.25, C. shehatae (2.7 × 107 cells mL−1); pH, 4.3; and temperature, 35∘C. pH with p-value 0.001 was found to be the most significant factor affecting SSF. The ethanol titre obtained in Taguchi optimized shake flask SSF was 2.0 g L−1 implying a 1.3-fold increase as compared to ethanol titre of 1.5 g L−1 in unoptimized shake flask SSF. A 1.5-fold gain in ethanol titre (3.1 g L−1) was obtained with the same substrate concentration in lab scale bioreactor on scaling up the shake flask SSF with Taguchi optimized process parameters.
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Lignocellulosic fermentation of wild grass employing recombinant hydrolytic enzymes and fermentative microbes with effective bioethanol recovery. BIOMED RESEARCH INTERNATIONAL 2013; 2013:386063. [PMID: 24089676 PMCID: PMC3782061 DOI: 10.1155/2013/386063] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 08/04/2013] [Indexed: 11/18/2022]
Abstract
Simultaneous saccharification and fermentation (SSF) studies of steam exploded and alkali pretreated different leafy biomass were accomplished by recombinant Clostridium thermocellum hydrolytic enzymes and fermentative microbes for bioethanol production. The recombinant C. thermocellum GH5 cellulase and GH43 hemicellulase genes expressed in Escherichia coli cells were grown in repetitive batch mode, with the aim of enhancing the cell biomass production and enzyme activity. In batch mode, the cell biomass (A600 nm) of E. coli cells and enzyme activities of GH5 cellulase and GH43 hemicellulase were 1.4 and 1.6 with 2.8 and 2.2 U·mg−1, which were augmented to 2.8 and 2.9 with 5.6 and 3.8 U·mg−1 in repetitive batch mode, respectively. Steam exploded wild grass (Achnatherum hymenoides) provided the best ethanol titres as compared to other biomasses. Mixed enzyme (GH5 cellulase, GH43 hemicellulase) mixed culture (Saccharomyces cerevisiae, Candida shehatae) system gave 2-fold higher ethanol titre than single enzyme (GH5 cellulase) single culture (Saccharomyces cerevisiae) system employing 1% (w/v) pretreated substrate. 5% (w/v) substrate gave 11.2 g·L−1 of ethanol at shake flask level which on scaling up to 2 L bioreactor resulted in 23 g·L−1 ethanol. 91.6% (v/v) ethanol was recovered by rotary evaporator with 21.2% purification efficiency.
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Waste valorization by biotechnological conversion into added value products. Appl Microbiol Biotechnol 2013; 97:6129-47. [DOI: 10.1007/s00253-013-5014-7] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 05/20/2013] [Accepted: 05/21/2013] [Indexed: 11/25/2022]
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Bioethanol production involving recombinant C. thermocellum hydrolytic hemicellulase and fermentative microbes. Appl Biochem Biotechnol 2012; 167:1475-88. [PMID: 22383050 DOI: 10.1007/s12010-012-9618-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Accepted: 02/14/2012] [Indexed: 10/28/2022]
Abstract
The enhancement of the biomass productivity of Escherichia coli cells harbouring the truncated 903 bp gene designated as glycoside hydrolase family 43 (GH43) from Clostridium thermocellum showing hemicellulase activity along with its further use in simultaneous saccharification and fermentation (SSF) process is described. (Phosphoric acid) H(3)PO(4)-acetone treatment and ammonia fibre expansion (AFEX) were the pretreatment strategies employed on the leafy biomass of mango, poplar, neem and asoka among various substrates owing to their high hemicellulose content. GH43 showed optimal activity at a temperature of 50 °C, pH 5.4 with stability over a pH range of 5.0-6.2. A 4-fold escalation in growth of the recombinant E. coli cells was observed when grown using repeated batch strategy in LB medium supplemented with glucose as co-substrate. Candida shehatae utilizing pentose sugars was employed for bioethanol production. AFEX pretreatment proved to be better over acid-acetone technique. The maximum ethanol concentration (1.44 g/L) was achieved for AFEX pretreated mango (1%, w/v) followed by poplar with an ethanol titre (1.32 g/L) in shake flask experiments. A 1.5-fold increase in ethanol titre (2.11 g/L) was achieved with mango (1%, w/v) in a SSF process using a table top 2-L bioreactor with 1 L working volume.
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