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Zhu YX, He M, Li KJ, Wang YK, Qian N, Wang ZF, Sheng H, Sui Y, Zhang DD, Zhang K, Qi L, Zheng DQ. Novel insights into the effects of 5-hydroxymethfurural on genomic instability and phenotypic evolution using a yeast model. Appl Environ Microbiol 2024; 90:e0164923. [PMID: 38108644 PMCID: PMC10807415 DOI: 10.1128/aem.01649-23] [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: 09/19/2023] [Accepted: 11/06/2023] [Indexed: 12/19/2023] Open
Abstract
5-Hydroxymethfurural (5-HMF) is naturally found in a variety of foods and beverages and represents a main inhibitor in the lignocellulosic hydrolysates used for fermentation. This study investigated the impact of 5-HMF on the genomic stability and phenotypic plasticity of the yeast Saccharomyces cerevisiae. Using next-generation sequencing technology, we examined the genomic alterations of diploid S. cerevisiae isolates that were subcultured on a medium containing 1.2 g/L 5-HMF. We found that in 5-HMF-treated cells, the rates of chromosome aneuploidy, large deletions/duplications, and loss of heterozygosity were elevated compared with that in untreated cells. 5-HMF exposure had a mild impact on the rate of point mutations but altered the mutation spectrum. Contrary to what was observed in untreated cells, more monosomy than trisomy occurred in 5-HMF-treated cells. The aneuploidy mutant with monosomic chromosome IX was more resistant to 5-HMF than the diploid parent strain because of the enhanced activity of alcohol dehydrogenase. Finally, we found that overexpression of ADH6 and ZWF1 effectively stabilized the yeast genome under 5-HMF stress. Our findings not only elucidated the global effect of 5-HMF on the genomic integrity of yeast but also provided novel insights into how chromosomal instability drives the environmental adaptability of eukaryotic cells.IMPORTANCESingle-cell microorganisms are exposed to a range of stressors in both natural and industrial settings. This study investigated the effects of 5-hydroxymethfurural (5-HMF), a major inhibitor found in baked foods and lignocellulosic hydrolysates, on the chromosomal instability of yeast. We examined the mechanisms leading to the distinct patterns of 5-HMF-induced genomic alterations and discovered that chromosomal loss, typically viewed as detrimental to cell growth under most conditions, can contribute to yeast tolerance to 5-HMF. Our results increased the understanding of how specific stressors stimulate genomic plasticity and environmental adaptation in yeast.
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Affiliation(s)
- Ying-Xuan Zhu
- Hainan Institute of Zhejiang University, Zhejiang University, Sanya, China
- Ocean College, Zhejiang University, Zhoushan, China
| | - Min He
- Hainan Institute of Zhejiang University, Zhejiang University, Sanya, China
| | - Ke-Jing Li
- Ocean College, Zhejiang University, Zhoushan, China
| | - Ye-Ke Wang
- College of Life Science, Zhejiang University, Hangzhou, China
| | - Ning Qian
- Ocean College, Zhejiang University, Zhoushan, China
| | - Ze-Fei Wang
- Hainan Institute of Zhejiang University, Zhejiang University, Sanya, China
| | - Huan Sheng
- Ocean College, Zhejiang University, Zhoushan, China
| | - Yang Sui
- Ocean College, Zhejiang University, Zhoushan, China
| | | | - Ke Zhang
- College of Life Science, Zhejiang University, Hangzhou, China
| | - Lei Qi
- Ocean College, Zhejiang University, Zhoushan, China
| | - Dao-Qiong Zheng
- Hainan Institute of Zhejiang University, Zhejiang University, Sanya, China
- Ocean College, Zhejiang University, Zhoushan, China
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Vardhan H, Sasmal S, Mohanty K. Detoxification of areca nut acid hydrolysate and production of xylitol by Candida tropicalis (MTCC 6192). Prep Biochem Biotechnol 2024; 54:61-72. [PMID: 37149784 DOI: 10.1080/10826068.2023.2207093] [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: 05/08/2023]
Abstract
Areca nut husk is the most promising alternative source of low-cost raw materials because it contains a considerable amount of five-carbon monosaccharide sugar in the form of xylose. This polymeric sugar can be isolated and transformed into a value-added chemical using fermentation. To extract sugars from areca nut husk fibers, preliminary pretreatment, such as dilute acid hydrolysis (H2SO4), was performed. The hemicellulosic hydrolysate of areca nut husk can produce xylitol through fermentation, but toxic components inhibit the growth of microorganisms. To overcome this, a series of detoxification treatments, including pH adjustment, activated charcoal, and ion exchange resin, were carried out to reduce the concentration of inhibitors in the hydrolysate. This study reports a remarkable 99% removal of inhibitors in the hemicellulosic hydrolysate. Subsequently, a fermentation process using Candida tropicalis (MTCC6192) was executed with the detoxified hemicellulosic hydrolysate of areca nut husk, yielding an optimum xylitol yield of 0.66 g/g. This study concludes that detoxification techniques like pH adjustment, activated charcoal, and ion exchange resins are the most economical and effective methods for eliminating toxic compounds in hemicellulosic hydrolysates. Therefore, the medium derived after detoxification from areca nut hydrolysate may be considered to have significant potential for xylitol production.
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Affiliation(s)
- Harsh Vardhan
- Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati, India
| | - Soumya Sasmal
- Department of Biotechnology, Visva-Bharati, Santiniketan, India
| | - Kaustubha Mohanty
- Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati, India
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Garmaroody ER, PahnehKolaei ND, Ramezani O, Hamedi S. Detoxification Approaches of Bagasse Pith Hydrolysate Affecting Xylitol Production by Rhodotorula mucilaginosa. Appl Biochem Biotechnol 2024; 196:129-144. [PMID: 37103733 DOI: 10.1007/s12010-023-04539-1] [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] [Accepted: 04/11/2023] [Indexed: 04/28/2023]
Abstract
In this study, the potential of bagasse pith (the waste of sugar and paper industry) was investigated for bio-xylitol production for the first time. Xylose-rich hydrolysate was prepared using 8% dilute sulfuric acid, at 120 °C for 90 min. Then, the acid-hydrolyzed solution was detoxified by individual overliming (OL), active carbon (AC), and their combination (OL+AC). The amounts of reducing sugars and inhibitors (furfural and hydroxyl methyl furfural) were measured after acid pre-treatment and detoxification process. Thereafter, xylitol was produced from detoxified hydrolysate by Rhodotorula mucilaginosa yeast. Results showed that after acid hydrolysis, the sugar yield was 20%. Detoxification by overliming and active carbon methods increased the reducing sugar content up to 65% and 36% and decreased the concentration of inhibitors to >90% and 16%, respectively. Also, combined detoxification caused an increase in the reducing sugar content (>73%) and a complete removal of inhibitors. The highest productivity of xylitol (0.366 g/g) by yeast was attained after the addition of 100 g/l non-detoxified xylose-rich hydrolysate into fermentation broth after 96 h, while the xylitol productivity enhanced to 0.496 g/g after adding the similar amount of xylose-rich hydrolysate detoxified by combined method (OL+AC2.5%).
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Affiliation(s)
- Esmaeil Rasooly Garmaroody
- Dept. of Bio-refinery, Faculty of New Technologies, Zirab Campus, Shahid Beheshti University, Savadkooh, Mazandaran, Iran
| | - Niloufar Davoodi PahnehKolaei
- Dept. of Bio-refinery, Faculty of New Technologies, Zirab Campus, Shahid Beheshti University, Savadkooh, Mazandaran, Iran
| | - Omid Ramezani
- Dept. of Bio-refinery, Faculty of New Technologies, Zirab Campus, Shahid Beheshti University, Savadkooh, Mazandaran, Iran.
| | - Sepideh Hamedi
- Dept. of Bio-refinery, Faculty of New Technologies, Zirab Campus, Shahid Beheshti University, Savadkooh, Mazandaran, Iran
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Wu G, Alriksson B, Jönsson LJ. Conditioning of pretreated birch by liquid-liquid organic extractions to improve yeast fermentability and enzymatic digestibility. RSC Adv 2023; 13:20023-20030. [PMID: 37409043 PMCID: PMC10318483 DOI: 10.1039/d3ra02210b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 06/23/2023] [Indexed: 07/07/2023] Open
Abstract
By-products from hydrothermal pretreatment of lignocellulosic biomass inhibit enzymatic saccharification and microbial fermentation. Three long-chain organic extractants (Alamine 336, Aliquat 336 and Cyanex 921) were compared to two conventional organic solvents (ethyl acetate and xylene) with regard to conditioning of birch wood pretreatment liquid (BWPL) for improved fermentation and saccharification. In the fermentation experiments, extraction with Cyanex 921 resulted in the best ethanol yield, 0.34 ± 0.02 g g-1 on initial fermentable sugars. Extraction with xylene also resulted in a relatively high yield, 0.29 ± 0.02 g g-1, while cultures consisting of untreated BWPL and BWPL treated with the other extractants exhibited no ethanol formation. Aliquat 336 was most efficient with regard to removing by-products, but the residual Aliquat after the extraction was toxic to yeast cells. Enzymatic digestibility increased by 19-33% after extraction with the long-chain organic extractants. The investigation demonstrates that conditioning with long-chain organic extractants has the potential to relieve inhibition of both enzymes and microbes.
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Affiliation(s)
- Guochao Wu
- Shandong Key Lab of Edible Mushroom Technology, School of Agriculture, Ludong University 264025 Yantai China
- Department of Chemistry, Umeå University SE-901 87 Umeå Sweden
| | - Björn Alriksson
- RISE Research Institutes of Sweden AB SE-891 22 Örnsköldsvik Sweden
| | - Leif J Jönsson
- Department of Chemistry, Umeå University SE-901 87 Umeå Sweden
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Surfactants, Biosurfactants, and Non-Catalytic Proteins as Key Molecules to Enhance Enzymatic Hydrolysis of Lignocellulosic Biomass. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27238180. [PMID: 36500273 PMCID: PMC9739445 DOI: 10.3390/molecules27238180] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/17/2022] [Accepted: 11/21/2022] [Indexed: 11/27/2022]
Abstract
Lignocellulosic biomass (LCB) has remained a latent alternative resource to be the main substitute for oil and its derivatives in a biorefinery concept. However, its complex structure and the underdeveloped technologies for its large-scale processing keep it in a state of constant study trying to establish a consolidated process. In intensive processes, enzymes have been shown to be important molecules for the fractionation and conversion of LCB into biofuels and high-value-added molecules. However, operational challenges must be overcome before enzyme technology can be the main resource for obtaining second-generation sugars. The use of additives is shown to be a suitable strategy to improve the saccharification process. This review describes the mechanisms, roles, and effects of using additives, such as surfactants, biosurfactants, and non-catalytic proteins, separately and integrated into the enzymatic hydrolysis process of lignocellulosic biomass. In doing so, it provides a technical background in which operational biomass processing hurdles such as solids and enzymatic loadings, pretreatment burdens, and the unproductive adsorption phenomenon can be addressed.
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Ujor VC, Okonkwo CC. Microbial detoxification of lignocellulosic biomass hydrolysates: Biochemical and molecular aspects, challenges, exploits and future perspectives. Front Bioeng Biotechnol 2022; 10:1061667. [PMID: 36483774 PMCID: PMC9723337 DOI: 10.3389/fbioe.2022.1061667] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 10/31/2022] [Indexed: 08/26/2023] Open
Abstract
Valorization of lignocellulosic biomass (LB) has the potential to secure sustainable energy production without impacting food insecurity, whist relieving over reliance on finite fossil fuels. Agro-derived lignocellulosic residues such as wheat straw, switchgrass, rice bran, and miscanthus have gained relevance as feedstocks for the production of biofuels and chemicals. However, the microorganisms employed in fermentative conversion of carbohydrates to fuels and chemicals are unable to efficiently utilize the sugars derived from LB due to co-production of lignocellulose-derived microbial inhibitory compounds (LDMICs) during LB pretreatment. LDMICs impact microbial growth by inhibition of specific enzymes, cause DNA and cell membrane damage, and elicit cellular redox imbalance. Over the past decade, success has been achieved with the removal of LDMICs prior to fermentation. However, LDMICs removal by chemical processes is often accompanied by sugar losses, which negatively impacts the overall production cost. Hence, in situ removal of LDMICs by fermentative organisms during the fermentation process has garnered considerable attention as the "go-to" approach for economical LDMICs detoxification and bio-chemicals production. In situ removal of LDMICs has been pursued by either engineering more robust biocatalysts or isolating novel microbial strains with the inherent capacity to mineralize or detoxify LDMICs to less toxic compounds. While some success has been made along this line, efficient detoxification and robust production of target bio-chemicals in lignocellulosic hydrolysates (LHs) under largely anaerobic fermentative conditions remains a lingering challenge. Consequently, LB remains an underutilized substrate for bio-chemicals production. In this review, the impact of microbial LH detoxification on overall target molecule production is discussed. Further, the biochemical pathways and mechanisms employed for in situ microbial detoxification of furanic LDMICs [e.g., furfural and 5-hydroxymethylfurfural (HMF)] and phenolic LDMICs (e.g., syringaldehyde, p-coumaric acid, 4-hydroxybenzaldehyde, vanillin, and ferulic acid) are discussed. More importantly, metabolic engineering strategies for the development of LDMIC-tolerant and bio-chemicals overproducing strains and processes are highlighted.
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Affiliation(s)
- Victor C. Ujor
- Metabolic Engineering and Fermentation Science Group, Department of Food Science, University of Wisconsin-Madison, Madison, WI, United States
| | - Christopher C. Okonkwo
- Biotechnology Program, College of Science, The Roux Institute, Northeastern University, Portland, ME, United States
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Zhong N, Chandra R, Yamamoto M, Leskinen T, Granström T, Saddler J. Sulphite addition during steam pretreatment enhanced both enzyme-mediated cellulose hydrolysis and ethanol production. BIORESOUR BIOPROCESS 2022; 9:71. [PMID: 38647560 PMCID: PMC10991184 DOI: 10.1186/s40643-022-00556-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 06/01/2022] [Indexed: 11/10/2022] Open
Abstract
Sulphite addition during steam pretreatment of softwoods under acidic, neutral and alkaline conditions was assessed to try to minimize lignin condensation. Although pretreatment under neutral/alkaline conditions resulted in effective lignin sulphonation, non-uniform size reduction was observed. In contrast, acidic sulphite steam treatment at 210 °C for 10 min resulted in homogenous particle size reduction and water-insoluble component that was 62% carbohydrate and 33% lignin. This carbohydrate-rich substrate was readily hydrolyzed and fermented which indicated the lack of fermentation inhibitors in the steam-pretreated whole slurry. The use of high solid loading (25% w/v) resulted in a hydrolysis yield of 58% at an enzyme loading of 40 mg protein/g glucan and efficient fermentation (46.6 g/L of ethanol). This indicated that the addition of acidic sulphite at the steam pretreatment of softwoods improved both the enzymatic hydrolysis and fermentation of steam-pretreated whole slurries.
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Affiliation(s)
- Na Zhong
- Department of Wood Science, Faculty of Forestry, Forest Products Biotechnology and Bioenergy Group, The University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada
- St1 Oy, Firdonkatu 2, Helsinki, Finland
| | - Richard Chandra
- Trinity Western University, 22500 University Dr, Langley, BC, Canada.
| | | | | | - Tom Granström
- VTT Technical Research Centre of Finland Ltd., 02044, Espoo, Finland
| | - Jack Saddler
- Department of Wood Science, Faculty of Forestry, Forest Products Biotechnology and Bioenergy Group, The University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada.
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8
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Wu J, Ebadian M, Kim KH, Kim CS, Saddler J. The use of steam pretreatment to enhance pellet durability and the enzyme-mediated hydrolysis of pellets to fermentable sugars. BIORESOURCE TECHNOLOGY 2022; 347:126731. [PMID: 35074465 DOI: 10.1016/j.biortech.2022.126731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 01/13/2022] [Accepted: 01/15/2022] [Indexed: 06/14/2023]
Abstract
Although densified wood pellets are an attractive biomass feedstock for bioenergy and biofuels production, partly due to their ease of transport, their friability and hygroscopic nature (attraction of moisture) have proven problematic in terms of storage and handling. Pre-steaming the biomass was shown to reduce the need for size reduction, significantly increasing pellet durability by relocating the plant cell wall lignin to the fibre surface and consequently enhancing binding between particles. Although steam pretreatment has been shown to facilitate enzyme-mediated hydrolysis of biomass, by increasing cellulose accessibility, drying and pelletization partially impeded enzymatic hydrolysis. However, the incorporation of alkaline deacetylation or neutral sulfonation step prior to pre-steaming was shown to mitigate many of the negative effects of drying. Although drying and pelletization did not significantly impact the redistribution of lignin, a mild mechanical refining step was shown to further enhance the hydrolysis of the cellulose component of the pelletized biomass.
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Affiliation(s)
- Jie Wu
- Forest Products Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver BC V6T 1Z4, Canada
| | - Mahmood Ebadian
- Forest Products Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver BC V6T 1Z4, Canada
| | - Kwang Ho Kim
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Chang Soo Kim
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Jack Saddler
- Forest Products Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver BC V6T 1Z4, Canada.
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Jaffur N, Jeetah P, Kumar G. A review on enzymes and pathways for manufacturing polyhydroxybutyrate from lignocellulosic materials. 3 Biotech 2021; 11:483. [PMID: 34790507 DOI: 10.1007/s13205-021-03009-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Accepted: 09/28/2021] [Indexed: 11/26/2022] Open
Abstract
Currently, major focus in the biopolymer field is being drawn on the exploitation of plant-based resources grounded on holistic sustainability trends to produce novel, affordable, biocompatible and environmentally safe polyhydroxyalkanoate biopolymers. The global PHA market, estimated at USD 62 Million in 2020, is predicted to grow by 11.2 and 14.2% between 2020-2024 and 2020-2025 correspondingly based on market research reports. The market is primarily driven by the growing demand for PHA products by the food packaging, biomedical, pharmaceutical, biofuel and agricultural sectors. One of the key limitations in the growth of the PHA market is the significantly higher production costs associated with pure carbon raw materials as compared to traditional polymers. Nonetheless, considerations such as consumer awareness on the toxicity of petroleum-based plastics and strict government regulations towards the prohibition of the use and trade of synthetic plastics are expected to boost the market growth rate. This study throws light on the production of polyhydroxybutyrate from lignocellulosic biomass using environmentally benign techniques via enzyme and microbial activities to assess its feasibility as a green substitute to conventional plastics. The novelty of the present study is to highlight the recent advances, pretreatment techniques to reduce the recalcitrance of lignocellulosic biomass such as dilute and concentrated acidic pretreatment, alkaline pretreatment, steam explosion, ammonia fibre explosion (AFEX), ball milling, biological pretreatment as well as novel emerging pretreatment techniques notably, high-pressure homogenizer, electron beam, high hydrostatic pressure, co-solvent enhanced lignocellulosic fractionation (CELF) pulsed-electric field, low temperature steep delignification (LTSD), microwave and ultrasound technologies. Additionally, inhibitory compounds and detoxification routes, fermentation downstream processes, life cycle and environmental impacts of recovered natural biopolymers, review green procurement policies in various countries, PHA strategies in line with the United Nations Sustainable Development Goals (SDGs) along with the fate of the spent polyhydroxybutyrate are outlined.
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Affiliation(s)
- Nausheen Jaffur
- Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Mauritius, Réduit, 80837 Mauritius
| | - Pratima Jeetah
- Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Mauritius, Réduit, 80837 Mauritius
| | - Gopalakrishnan Kumar
- Institute of Chemistry, Bioscience and Environmental Engineering, Faculty of Science and Technology, University of Stavanger, Stavanger, Norway
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Hoang AT, Nizetic S, Ong HC, Chong CT, Atabani AE, Pham VV. Acid-based lignocellulosic biomass biorefinery for bioenergy production: Advantages, application constraints, and perspectives. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 296:113194. [PMID: 34243094 DOI: 10.1016/j.jenvman.2021.113194] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 06/14/2021] [Accepted: 06/29/2021] [Indexed: 06/13/2023]
Abstract
The production of chemicals and fuels from renewable biomass with the primary aim of reducing carbon footprints has recently become one of the central points of interest. The use of lignocellulosic biomass for energy production is believed to meet the main criteria of maximizing the available global energy source and minimizing pollutant emissions. However, before usage in bioenergy production, lignocellulosic biomass needs to undergo several processes, among which biomass pretreatment plays an important role in the yield, productivity, and quality of the products. Acid-based pretreatment, one of the existing methods applied for lignocellulosic biomass pretreatment, has several advantages, such as short operating time and high efficiency. A thorough analysis of the characteristics of acid-based biomass pretreatment is presented in this review. The environmental concerns and future challenges involved in using acid pretreatment methods are discussed in detail to achieve clean and sustainable bioenergy production. The application of acid to biomass pretreatment is considered an effective process for biorefineries that aim to optimize the production of desired products while minimizing the by-products.
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Affiliation(s)
- Anh Tuan Hoang
- Institute of Engineering, Ho Chi Minh City University of Technology (HUTECH), Ho Chi Minh City, Viet Nam.
| | - Sandro Nizetic
- University of Split, FESB, Rudjera Boskovica 32, 21000, Split, Croatia
| | - Hwai Chyuan Ong
- Centre for Green Technology, Faculty of Engineering and IT, University of Technology Sydney, NSW, 2007, Australia.
| | - Cheng Tung Chong
- China-UK Low Carbon College, Shanghai Jiao Tong University, Lingang, Shanghai, 201306, China
| | - A E Atabani
- Alternative Fuels Research Laboratroy (AFRL), Energy Division, Department of Mechanical Engineering, Faculty of Engineering, Erciyes University, 38039, Kayseri, Turkey
| | - Van Viet Pham
- Institute of Maritime, Ho Chi Minh City University of Transport, Ho Chi Minh City, Viet Nam.
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Chanda K, Mozumder AB, Chorei R, Gogoi RK, Prasad HK. A Lignocellulolytic Colletotrichum sp. OH with Broad-Spectrum Tolerance to Lignocellulosic Pretreatment Compounds and Derivatives and the Efficiency to Produce Hydrogen Peroxide and 5-Hydroxymethylfurfural Tolerant Cellulases. J Fungi (Basel) 2021; 7:785. [PMID: 34682207 PMCID: PMC8540663 DOI: 10.3390/jof7100785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/04/2021] [Accepted: 09/07/2021] [Indexed: 10/25/2022] Open
Abstract
Fungal endophytes are an emerging source of novel traits and biomolecules suitable for lignocellulosic biomass treatment. This work documents the toxicity tolerance of Colletotrichum sp. OH toward various lignocellulosic pretreatment-derived inhibitors. The effects of aldehydes (vanillin, p-hydroxybenzaldehyde, furfural, 5-hydroxymethylfurfural; HMF), acids (gallic, formic, levulinic, and p-hydroxybenzoic acid), phenolics (hydroquinone, p-coumaric acid), and two pretreatment chemicals (hydrogen peroxide and ionic liquid), on the mycelium growth, biomass accumulation, and lignocellulolytic enzyme activities, were tested. The reported Colletotrichum sp. OH was naturally tolerant to high concentrations of single inhibitors like HMF (IC50; 17.5 mM), levulinic acid (IC50; 29.7 mM), hydroquinone (IC50; 10.76 mM), and H2O2 (IC50; 50 mM). The lignocellulolytic enzymes displayed a wide range of single and mixed inhibitor tolerance profiles. The enzymes β-glucosidase and endoglucanase showed H2O2- and HMF-dependent activity enhancements. The enzyme β-glucosidase activity was 34% higher in 75 mM and retained 20% activity in 125 mM H2O2. Further, β-glucosidase activity increased to 24 and 32% in the presence of 17.76 and 8.8 mM HMF. This research suggests that the Colletotrichum sp. OH, or its enzymes, can be used to pretreat plant biomass, hydrolyze it, and remove inhibitory by-products.
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Affiliation(s)
| | | | | | | | - Himanshu Kishore Prasad
- Department of Life Science and Bioinformatics, Assam University, Silchar 788011, India; (K.C.); (A.B.M.); (R.C.); (R.K.G.)
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12
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Zhou Z, Zhou H, Zhang J. Development of wheat bran hydrolysate as Komagataella phaffii medium for heterologous protein production. Bioprocess Biosyst Eng 2021; 44:2645-2654. [PMID: 34468865 DOI: 10.1007/s00449-021-02633-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 08/29/2021] [Indexed: 12/30/2022]
Abstract
Developing a Komagataella phaffii (K. phaffii, named as Pichia pastoris formerly) medium using wheat bran hydrolysate (WBH) is a potential approach for wheat bran utilization and heterologous protein by K. phaffii because K. phaffii is used as protein producer by researchers and engineers widely. In this research, the detoxification process of WBH was optimized to obtain the final procedure as pH adjusting to 10 by calcium hydroxide addition, then, 2.0 g/L active carbon absorption followed by 1 h shaking and 3,600 × g centrifugation for 10 min, finally, 3.75 mmol/L sodium thiosulfate addition for 10 min shaking followed by 3,600 × g centrifugation for 10 min. Recombinant K. phaffii-xynB harboring xylanase B gene from Aspergillus niger ATCC 1015 under alcohol oxidase 1 promoter (PAOX1) was cultivated in detoxified WBH expressing 1059.8 U/mL xylanase B which was 90.9% of that in complex medium from Pichia protocols. These researches built a solid base for detoxified WBH as a low-cost medium of K. phaffii to express heterologous protein, also provided a bright outlet for wheat bran utilization.
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Affiliation(s)
- Ziwei Zhou
- Shanghai Engineering Research Center for Food Rapid Detection, Institute of Food Science and Engineering, School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, 516 Jungong Road, Shanghai, 200093, People's Republic of China
| | - Hualan Zhou
- Shanghai Engineering Research Center for Food Rapid Detection, Institute of Food Science and Engineering, School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, 516 Jungong Road, Shanghai, 200093, People's Republic of China
| | - Jianguo Zhang
- Shanghai Engineering Research Center for Food Rapid Detection, Institute of Food Science and Engineering, School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, 516 Jungong Road, Shanghai, 200093, People's Republic of China.
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13
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Factors Affecting Detoxification of Softwood Enzymatic Hydrolysates Using Sodium Dithionite. Processes (Basel) 2021. [DOI: 10.3390/pr9050887] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Conditioning of lignocellulosic hydrolysates with sulfur oxyanions, such as dithionite, is one of the most potent methods to improve the fermentability by counteracting effects of inhibitory by-products generated during hydrothermal pretreatment under acidic conditions. The effects of pH, treatment temperature, and dithionite dosage were explored in experiments with softwood hydrolysates, sodium dithionite, and Saccharomyces cerevisiae yeast. Treatments with dithionite at pH 5.5 or 8.5 gave similar results with regard to ethanol productivity and yield on initial glucose, and both were always at least ~20% higher than for treatment at pH 2.5. Experiments in the dithionite concentration range 5.0–12.5 mM and the temperature range 23–110 °C indicated that treatment at around 75 °C and using intermediate dithionite dosage was the best option (p ≤ 0.05). The investigation indicates that selection of the optimal temperature and dithionite dosage offers great benefits for the efficient fermentation of hydrolysates from lignin-rich biomass, such as softwood residues.
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Vanmarcke G, Demeke MM, Foulquié-Moreno MR, Thevelein JM. Identification of the major fermentation inhibitors of recombinant 2G yeasts in diverse lignocellulose hydrolysates. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:92. [PMID: 33836811 PMCID: PMC8034183 DOI: 10.1186/s13068-021-01935-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Accepted: 03/20/2021] [Indexed: 05/16/2023]
Abstract
BACKGROUND Presence of inhibitory chemicals in lignocellulose hydrolysates is a major hurdle for production of second-generation bioethanol. Especially cheaper pre-treatment methods that ensure an economical viable production process generate high levels of these inhibitory chemicals. The effect of several of these inhibitors has been extensively studied with non-xylose-fermenting laboratory strains, in synthetic media, and usually as single inhibitors, or with inhibitor concentrations much higher than those found in lignocellulose hydrolysates. However, the relevance of individual inhibitors in inhibitor-rich lignocellulose hydrolysates has remained unclear. RESULTS The relative importance for inhibition of ethanol fermentation by two industrial second-generation yeast strains in five lignocellulose hydrolysates, from bagasse, corn cobs and spruce, has now been investigated by spiking higher concentrations of each compound in a concentration range relevant for industrial hydrolysates. The strongest inhibition was observed with industrially relevant concentrations of furfural causing partial inhibition of both D-glucose and D-xylose consumption. Addition of 3 or 6 g/L furfural strongly reduced the ethanol titer obtained with strain MD4 in all hydrolysates evaluated, in a range of 34 to 51% and of 77 to 86%, respectively. This was followed by 5-hydroxymethylfurfural, acetic acid and formic acid, for which in general, industrially relevant concentrations caused partial inhibition of D-xylose fermentation. On the other hand, spiking with levulinic acid, 4-hydroxybenzaldehyde, 4-hydroxybenzoic acid or vanillin caused little inhibition compared to unspiked hydrolysate. The further evolved MD4 strain generally showed superior performance compared to the previously developed strain GSE16-T18. CONCLUSION The results highlight the importance of individual inhibitor evaluation in a medium containing a genuine mix of inhibitors as well as the ethanol that is produced by the fermentation. They also highlight the potential of increasing yeast inhibitor tolerance for improving industrial process economics.
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Affiliation(s)
- Gert Vanmarcke
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Department of Biology, KU Leuven, Kasteelpark Arenberg 31, 3001, Leuven-Heverlee, Flanders, Belgium
- Center for Microbiology, VIB, Kasteelpark Arenberg 31, 3001, Leuven-Heverlee, Flanders, Belgium
| | - Mekonnen M Demeke
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Department of Biology, KU Leuven, Kasteelpark Arenberg 31, 3001, Leuven-Heverlee, Flanders, Belgium
- Center for Microbiology, VIB, Kasteelpark Arenberg 31, 3001, Leuven-Heverlee, Flanders, Belgium
| | - Maria R Foulquié-Moreno
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Department of Biology, KU Leuven, Kasteelpark Arenberg 31, 3001, Leuven-Heverlee, Flanders, Belgium
- Center for Microbiology, VIB, Kasteelpark Arenberg 31, 3001, Leuven-Heverlee, Flanders, Belgium
| | - Johan M Thevelein
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Department of Biology, KU Leuven, Kasteelpark Arenberg 31, 3001, Leuven-Heverlee, Flanders, Belgium.
- Center for Microbiology, VIB, Kasteelpark Arenberg 31, 3001, Leuven-Heverlee, Flanders, Belgium.
- NovelYeast bv, Open Bio-Incubator, Erasmus High School, Laarbeeklaan 121, Jette, 1090, Brussels, Belgium.
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15
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Gutmann F, Jann C, Pereira F, Johansson A, Steinmetz LM, Patil KR. CRISPRi screens reveal genes modulating yeast growth in lignocellulose hydrolysate. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:41. [PMID: 33568224 PMCID: PMC7874482 DOI: 10.1186/s13068-021-01880-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 01/07/2021] [Indexed: 05/13/2023]
Abstract
BACKGROUND Baker's yeast is a widely used eukaryotic cell factory, producing a diverse range of compounds including biofuels and fine chemicals. The use of lignocellulose as feedstock offers the opportunity to run these processes in an environmentally sustainable way. However, the required hydrolysis pretreatment of lignocellulosic material releases toxic compounds that hamper yeast growth and consequently productivity. RESULTS Here, we employ CRISPR interference in S. cerevisiae to identify genes modulating fermentative growth in plant hydrolysate and in presence of lignocellulosic toxins. We find that at least one-third of hydrolysate-associated gene functions are explained by effects of known toxic compounds, such as the decreased growth of YAP1 or HAA1, or increased growth of DOT6 knock-down strains in hydrolysate. CONCLUSION Our study confirms previously known genetic elements and uncovers new targets towards designing more robust yeast strains for the utilization of lignocellulose hydrolysate as sustainable feedstock, and, more broadly, paves the way for applying CRISPRi screens to improve industrial fermentation processes.
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Affiliation(s)
- Friederike Gutmann
- European Molecular Biology Laboratory (EMBL), Structural and Cell Biology Unit, 69117, Heidelberg, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125, Berlin, Germany
| | - Cosimo Jann
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117, Heidelberg, Germany.
- Department of Biology, Institute of Biochemistry, ETH Zurich, Zurich, Switzerland.
| | - Filipa Pereira
- European Molecular Biology Laboratory (EMBL), Structural and Cell Biology Unit, 69117, Heidelberg, Germany.
| | - Andreas Johansson
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117, Heidelberg, Germany
| | - Lars M Steinmetz
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117, Heidelberg, Germany
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, 94305, USA
- Stanford Genome Technology Center, Palo Alto, CA, 94304, USA
| | - Kiran R Patil
- European Molecular Biology Laboratory (EMBL), Structural and Cell Biology Unit, 69117, Heidelberg, Germany.
- MRC Toxicology Unit, University of Cambridge, Cambridge, UK.
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16
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Ilanidis D, Wu G, Stagge S, Martín C, Jönsson LJ. Effects of redox environment on hydrothermal pretreatment of lignocellulosic biomass under acidic conditions. BIORESOURCE TECHNOLOGY 2021; 319:124211. [PMID: 33045548 DOI: 10.1016/j.biortech.2020.124211] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/28/2020] [Accepted: 09/29/2020] [Indexed: 05/23/2023]
Abstract
The effects of the redox environment on acidic hydrothermal pretreatment were investigated in experiments with sugarcane bagasse (190 °C, 14 min) and Norway spruce (205 °C, 5 min). To modulate the redox environment, pretreatment was performed without gas addition, with N2, or with O2. Analyses covered pretreated solids, pretreatment liquids, condensates, enzymatic digestibility, and inhibitory effects of pretreatment liquids on yeast. Addition of gas, especially O2, resulted in increased severity, as reflected by up to 18 percent units lower recoveries of pretreated solids, up to 31 percent units lower glucan recoveries, improved hemicellulose removal, formation of pseudo-lignin, improved overall glucan conversion, and increased concentrations of several microbial inhibitors. Some inhibitors, such as formaldehyde and coniferyl aldehyde, did not, however, follow that pattern. TAC (Total Aromatic Content) values reflected inhibitory effects of pretreatment liquids. This study demonstrates how gas addition can be used to modulate the severity of acidic hydrothermal pretreatment.
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Affiliation(s)
| | - Guochao Wu
- Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden
| | - Stefan Stagge
- Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden
| | - Carlos Martín
- Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden
| | - Leif J Jönsson
- Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden.
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17
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Wan L, Gao Z, Wu B, Cao F, Jiang M, Wei P, Jia H. Hydrolysis of Corncob Hemicellulose by Solid Acid Sulfated Zirconia and Its Evaluation in Xylitol Production. Appl Biochem Biotechnol 2020; 193:205-217. [PMID: 32844352 DOI: 10.1007/s12010-020-03412-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 08/12/2020] [Indexed: 11/28/2022]
Abstract
Corncob is an abundant agricultural residue containing high content of hemicellulose. In this paper, the hemicellulosic hydrolysate was prepared from the hydrolysis of corncob using the solid acid sulfated zirconia as a catalyst. According to response surface analysis experiments, the optimum conditions for preparing hemicellulosic hydrolysate catalyzed by sulfated zirconia were determined as follows: solid (sulfated zirconia)-solid (corncob) ratio was 0.33, solid (corncob)-liquid (water) ratio was 0.09, temperature was 153 °C, and time was 5.3 h. Under the optimized conditions, the soluble sugar concentration was 30.12 g/L with a yield of 033 g/g corncob. Subsequently, xylitol production from the resulting hemicellulosic hydrolysate was demonstrated by Candida tropicalis, and results showed that the yield of xylitol from the hemicellulosic hydrolysate could be significantly improved on a basis of decolorization and detoxification before fermentation. The maximum yield of xylitol from the hemicellulosic hydrolysate fermented by C. tropicalis was 0.76 g/g. This study provides a new attempt for xylitol production from the hemicellulosic hydrolysate.
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Affiliation(s)
- Lijun Wan
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211816, China
| | - Zhen Gao
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211816, China
| | - Bin Wu
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211816, China
| | - Fei Cao
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211816, China
| | - Min Jiang
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211816, China
| | - Ping Wei
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211816, China
| | - Honghua Jia
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211816, China.
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18
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Magalhães AI, de Carvalho JC, Thoms JF, Souza Silva R, Soccol CR. Second-generation itaconic acid: An alternative product for biorefineries? BIORESOURCE TECHNOLOGY 2020; 308:123319. [PMID: 32278999 DOI: 10.1016/j.biortech.2020.123319] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 04/02/2020] [Accepted: 04/03/2020] [Indexed: 06/11/2023]
Abstract
The ability to produce second-generation itaconic acid by Aspergillus terreus, and the inhibitory effects of hydrolysis by-products on the fermentation were evaluated by cultivation in a synthetic medium containing components usually present in a real hydrolysate broth from lignocellulosic biomasses. The results showed that A. terreus NRRL 1960 can produce itaconic acid and consume xylose completely, but the conversion is less than the fermentation using only glucose. In addition, compared to fermentation of glucose, or even xylose, the mix of both sugars resulted in a lower itaconic acid yield. In the inhibitory test, the final itaconic acid titer was reduced by acetic acid, furfural, and 5-hydroxymethylfurfural concentrations of, respectively, 188, 175, and 700 mg L-1. However, the presence of any amount of acetic acid proved to be detrimental to itaconic acid production. This research sheds some light on doubts about the biorefinery implementation of itaconic acid production.
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Affiliation(s)
- Antonio Irineudo Magalhães
- Federal University of Paraná, Department of Bioprocess Engineering and Biotechnology, P.O. Box 19011, ZIP Code 81531-990, Curitiba, Paraná, Brazil
| | - Júlio Cesar de Carvalho
- Federal University of Paraná, Department of Bioprocess Engineering and Biotechnology, P.O. Box 19011, ZIP Code 81531-990, Curitiba, Paraná, Brazil.
| | - Juliano Feliz Thoms
- Federal University of Paraná, Department of Bioprocess Engineering and Biotechnology, P.O. Box 19011, ZIP Code 81531-990, Curitiba, Paraná, Brazil
| | - Rafaeli Souza Silva
- Federal University of Paraná, Department of Bioprocess Engineering and Biotechnology, P.O. Box 19011, ZIP Code 81531-990, Curitiba, Paraná, Brazil
| | - Carlos Ricardo Soccol
- Federal University of Paraná, Department of Bioprocess Engineering and Biotechnology, P.O. Box 19011, ZIP Code 81531-990, Curitiba, Paraná, Brazil
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19
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Pretreatment and Detoxification of Acid-Treated Wood Hydrolysates for Pyruvate Production by an Engineered Consortium of Escherichia coli. Appl Biochem Biotechnol 2020; 192:243-256. [PMID: 32372381 DOI: 10.1007/s12010-020-03320-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 04/23/2020] [Indexed: 10/24/2022]
Abstract
The biorefinery concept makes use of renewable lignocellulosic biomass to produce commodities sustainably. A synthetic microbial consortium can enable the simultaneous utilization of sugars such as glucose and xylose to produce biochemicals, where each consortium member converts one sugar into the target product. In this study, woody biomass was used to generate glucose and xylose after pretreatment with 20% (w/v) sulfuric acid and 60-min reaction time. We compared several strategies for detoxification with charcoal and sodium borohydride treatments to improve the fermentability of this hydrolysate in a defined medium for the production of the growth-associated product pyruvate. In shake flask culture, the highest pyruvate yield on xylose of 0.8 g/g was found using pH 6 charcoal-treated hydrolysate. In bioreactor studies, a consortium of two engineered E. coli strains converted the mixture of glucose and xylose in batch studies to 12.8 ± 2.7 g/L pyruvate in 13 h. These results demonstrate that lignocellulosic biomass as the sole carbon source can be used to produce growth-related products after employing suitable detoxification strategies.
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20
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Ladeira Ázar RIS, Bordignon-Junior SE, Laufer C, Specht J, Ferrier D, Kim D. Effect of Lignin Content on Cellulolytic Saccharification of Liquid Hot Water Pretreated Sugarcane Bagasse. Molecules 2020; 25:molecules25030623. [PMID: 32023910 PMCID: PMC7037451 DOI: 10.3390/molecules25030623] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 01/22/2020] [Accepted: 01/28/2020] [Indexed: 11/16/2022] Open
Abstract
Lignin contributes to the rigid structure of the plant cell wall and is partially responsible for the recalcitrance of lignocellulosic materials to enzymatic digestion. Overcoming this recalcitrance is one the most critical issues in a sugar-flat form process. This study addresses the effect of low lignin sugarcane bagasse on enzymatic hydrolysis after liquid hot water pretreatment at 190 °C and 20 min (severity factor: 3.95). The hydrolysis of bagasse from a sugarcane line selected for a relatively low lignin content, gave an 89.7% yield of cellulose conversion to glucose at 40 FPU/g glucan versus a 68.3% yield from a comparably treated bagasse from the high lignin bred line. A lower enzyme loading of 5 FPU/g glucan (equivalent to 3.2 FPU/g total solids) resulted in 31.4% and 21.9% conversion yields, respectively, for low and high lignin samples, suggesting the significance of lignin content in the saccharification process. Further increases in the enzymatic conversion of cellulose to glucose were achieved when the bagasse sample was pre-incubated with a lignin blocking agent, e.g., bovine serum albumin (50 mg BSA/g glucan) at 50 °C for 1 h prior to an actual saccharification. In this work, we have demonstrated that even relatively small differences in lignin content can result in considerably increased sugar production, which supports the dissimilarity of bagasse lignin content and its effects on cellulose digestibility. The increased glucose yields with the addition of BSA helped to decrease the inhibition of non-productive absorption of cellulose enzymes onto lignin and solid residual lignin fractions.
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Affiliation(s)
- Rafaela I. S. Ladeira Ázar
- Department of Biochemistry and Molecular Biology, BIOAGRO, Federal University of Viçosa, Viçosa, Minas Gerais 36570-000, Brazil;
| | - Sidnei Emilio Bordignon-Junior
- Laboratory of Biochemistry and Applied Microbiology, São Paulo State University (UNESP), IBILCE, 2265 Cristóvão Colombo, São José do Rio Preto 15054-000, São Paulo, Brazil;
| | - Craig Laufer
- Department of Biology, Hood College, 401 Rosemont Avenue, Frederick, MD 21701, USA; (C.L.); (J.S.); (D.F.)
| | - Jordan Specht
- Department of Biology, Hood College, 401 Rosemont Avenue, Frederick, MD 21701, USA; (C.L.); (J.S.); (D.F.)
| | - Drew Ferrier
- Department of Biology, Hood College, 401 Rosemont Avenue, Frederick, MD 21701, USA; (C.L.); (J.S.); (D.F.)
| | - Daehwan Kim
- Department of Biology, Hood College, 401 Rosemont Avenue, Frederick, MD 21701, USA; (C.L.); (J.S.); (D.F.)
- Correspondence: ; Tel.: +1-765-637-8603; Fax: +1-301-696-3667
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21
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Shi A, Yomano LP, York SW, Zheng H, Shanmugam KT, Ingram LO. Chromosomal mutations in Escherichia coli that improve tolerance to nonvolatile side-products from dilute acid treatment of sugarcane bagasse. Biotechnol Bioeng 2019; 117:85-95. [PMID: 31612993 DOI: 10.1002/bit.27189] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 09/16/2019] [Accepted: 10/10/2019] [Indexed: 01/03/2023]
Abstract
Lignocellulosic biomass provides attractive nonfood carbohydrates for the production of ethanol, and dilute acid pretreatment is a biomass-independent process for access to these carbohydrates. However, this pretreatment also releases volatile and nonvolatile inhibitors of fermenting microorganisms. To identify unique gene products contributing to sensitivity/tolerance to nonvolatile inhibitors, ethanologenic Escherichia coli strain LY180 was adapted for growth in vacuum-treated sugarcane bagasse acid hydrolysate (VBHz) lacking furfural and other volatile inhibitors. A mutant, strain AQ15, obtained after approximately 500 generations of growth in VBHz, grew and fermented the sugars in a medium with 50% VBHz. Comparative genome sequence analysis of strains AQ15 and LY180 revealed 95 mutations in strain AQ15. Six of these mutations were also found in strain SL112, an independent inhibitor-tolerant derivative of strain LY180. Among these six mutations, null mutations in mdh and bacA were identified as contributing factors to VBHz tolerance in strain AQ15, based on the genetic and physiological analysis. The deletion of either gene in strain LY180 increased tolerance to VBHz from approximately 30-50% (vol/vol). Considering the location and physiological role of the two enzymes in the cell, it is likely that the two enzymes contribute to the VBHz sensitivity of ethanologenic E. coli by different mechanisms.
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Affiliation(s)
- Aiqin Shi
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida.,Department of Biochemistry and Molecular Biology, Penn State College of Medicine, Hershey, Pennsylvania
| | - Lorraine P Yomano
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida
| | - Sean W York
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida
| | - Huabao Zheng
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida.,Key Laboratory of Soil Contamination Bioremediation of Zhejiang Province, College of Environmental and Resource Sciences, Zhejiang A & F University, Hangzhou, China
| | - Keelnatham T Shanmugam
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida
| | - Lonnie O Ingram
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida
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22
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Zhao Q, Wang L, Chen H. Effect of Novel Pretreatment of Steam Explosion Associated with Ammonium Sulfite Process on Enzymatic Hydrolysis of Corn Straw. Appl Biochem Biotechnol 2019; 189:485-497. [PMID: 31049884 DOI: 10.1007/s12010-019-03018-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 03/27/2019] [Indexed: 01/06/2023]
Abstract
Effective pretreatment process to improve enzymatic saccharification and decrease inhibitors generation is a key operation involved in the lignocellulosic bioconversion. The pretreatment of steam explosion associated with ammonium sulfite (SEAS) process was carried out to investigate the effect on enzymatic hydrolysis and fermentation production as a combinatorial pretreatment. Results showed that after pretreatment (1.0 MPa, 30 min, 20%w/w ammonium sulfite added), the phenolic inhibitors derived from lignin significantly removed (37.8%), which transformed to chemical humic acid (humic acid and fulvic acid) mostly. Sugar conversion (glucan (77.8%) and xylan (73.3%)) and ethanol concentration (40.8 g/L) of combinatorial pretreated samples were increased by 24.7% and 33.8%, respectively, compared with steam explosion (SE) pretreated samples. FT-IR and elemental analysis results indicated that the lignin structure changed and aromatization degree increased after SEAS pretreatment. In addition, the ratio of C/N decreased and compost maturity degree increased with the holding time. The effect on the growth of wheat seedlings of soluble fulvic acid solution from combinatorial pretreatment was investigated, where below 1% (w/w) concentration did contribute to growth. Therefore, one-step chemical pretreatment process could be provided for inhibitors removal, enzymatic saccharification increase, and chemical humic acid formation as well.
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Affiliation(s)
- Qihong Zhao
- State Key Laboratory of Biochemical Engineering, Beijing Key Laboratory of Biomass Refining Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, People's Republic of China.,University of Chinese Academy of Sciences, Beijing, 100190, People's Republic of China
| | - Lan Wang
- State Key Laboratory of Biochemical Engineering, Beijing Key Laboratory of Biomass Refining Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, People's Republic of China.
| | - Hongzhang Chen
- State Key Laboratory of Biochemical Engineering, Beijing Key Laboratory of Biomass Refining Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, People's Republic of China
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23
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Production of cellulosic butyrate and 3-hydroxybutyrate in engineered Escherichia coli. Appl Microbiol Biotechnol 2019; 103:5215-5230. [DOI: 10.1007/s00253-019-09815-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 03/20/2019] [Accepted: 03/31/2019] [Indexed: 01/17/2023]
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24
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Silva PC, Domingues L, Collins T, Oliveira R, Johansson B. Quantitative assessment of DNA damage in the industrial ethanol production strain Saccharomyces cerevisiae PE-2. FEMS Yeast Res 2018; 18:5097783. [PMID: 30219865 DOI: 10.1093/femsyr/foy101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 09/12/2018] [Indexed: 11/14/2022] Open
Abstract
Lignocellulosic hydrolysates remain one of the most abundantly used substrates for the sustainable production of second generation fuels and chemicals with Saccharomyces cerevisiae. Nevertheless, fermentation inhibitors such as acetic acid, furfural and hydroxymethylfurfural are formed during the process and can lead to slow or stuck fermentations and/or act as genotoxic agents leading to production strain genetic instability. We have developed a novel dominant deletion (DEL) cassette assay for quantification of DNA damage in both wild-type and industrial yeast strains. Using this assay, the ethanol production strain S. cerevisiae PE-2 was shown to be more resistant to hydrogen peroxide and furfural than the laboratory DEL strain RS112. Indeed, the PE-2 strain also showed a lower tendency for recombination, consistent with a more efficient DNA protection. The dominant DEL assay presented herein should prove to be a useful tool in the selection of robust yeast strains and process conditions for second generation feedstock fermentations.
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Affiliation(s)
| | - Lucília Domingues
- CEB-Centre of Biological Engineering, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal
| | - Tony Collins
- CBMA - Center of Molecular and Environmental Biology
| | - Rui Oliveira
- CEB-Centre of Biological Engineering, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal.,Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
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25
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Sparlinek L, Leitner V, Kamm B. Statistical optimisation of enzymatic detoxification with laccase from Trametes versicolor for spent sulphite liquors using a novel in-situ NMR method. J Biotechnol 2018; 284:63-67. [DOI: 10.1016/j.jbiotec.2018.07.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 07/09/2018] [Accepted: 07/19/2018] [Indexed: 01/01/2023]
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26
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Guan W, Shi S, Blersch D. Effects of Tween 80 on fermentative butanol production from alkali-pretreated switchgrass. Biochem Eng J 2018. [DOI: 10.1016/j.bej.2018.03.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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27
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Zhai R, Hu J, Saddler JN. Minimizing cellulase inhibition of whole slurry biomass hydrolysis through the addition of carbocation scavengers during acid-catalyzed pretreatment. BIORESOURCE TECHNOLOGY 2018; 258:12-17. [PMID: 29518686 DOI: 10.1016/j.biortech.2018.02.124] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2018] [Revised: 02/25/2018] [Accepted: 02/26/2018] [Indexed: 05/20/2023]
Abstract
The aim of this work was to study how to minimize cellulase inhibition of whole slurry biomass hydrolysis through addition of carbocation scavengers during acid-catalyzed pretreatment. Various potential carbocation scavengers were compared and their inhibition mitigating effects towards the hydrolytic performance of cellulase enzymes was assessed. The results indicated that the addition of carbocation scavengers during the pretreatment process could not only alleviate the inhibitory effect of the phenolics on the enzymatic hydrolysis but also increase the accessibility of cellulases to the pretreated substrates. It appeared that lignin-derived compounds such as 4-hydroxybenzoic acid, vanillic acid, syringic acid could all serve as efficient scavengers to alleviate the inhibitory effect of phenolics on cellulose hydrolysis where the syringic acid showed the best mitigating effect. By combining the carbocation scavengers in the pretreatment process, an improved cellulose hydrolysis of the pretreated whole slurry could be achieved without any post detoxification step.
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Affiliation(s)
- Rui Zhai
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, 200 Xiaolingwei Street, Nanjing 210094, China; Forest Products Biotechnology and Bioenergy Group, Department of Wood Science, Faculty of Forestry, The University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada
| | - Jinguang Hu
- Forest Products Biotechnology and Bioenergy Group, Department of Wood Science, Faculty of Forestry, The University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada.
| | - Jack N Saddler
- Forest Products Biotechnology and Bioenergy Group, Department of Wood Science, Faculty of Forestry, The University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada
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Detoxification of Organosolv-Pretreated Pine Prehydrolysates with Anion Resin and Cysteine for Butanol Fermentation. Appl Biochem Biotechnol 2018; 186:662-680. [PMID: 29717408 DOI: 10.1007/s12010-018-2769-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 04/23/2018] [Indexed: 10/17/2022]
Abstract
Bioconversion of lignocellulose to biofuels suffers from the degradation compounds formed during pretreatment and acid hydrolysis. In order to achieve an efficient biomass to biofuel conversion, detoxification is often required before enzymatic hydrolysis and microbial fermentation. Prehydrolysates from ethanol organosolv-pretreated pine wood were used as substrates in butanol fermentation in this study. Six detoxification approaches were studied and compared, including overliming, anion exchange resin, nonionic resin, laccase, activated carbon, and cysteine. It was observed that detoxification by anion exchange resin was the most effective method. The final butanol yield after anion exchange resin treatment was comparable to the control group, but the fermentation was delayed for 72 h. The addition of Ca(OH)2 was found to alleviate this delay and improve the fermentation efficiency. The combination of Ca(OH)2 and anion exchange resin resulted in completion of fermentation within 72 h and acetone-butanol-ethanol (ABE) production of 11.11 g/L, corresponding to a yield of 0.21 g/g sugar. The cysteine detoxification also resulted in good detoxification performance, but promoted fermentation towards acid production (8.90 g/L). The effect of salt on ABE fermentation was assessed and the possible role of Ca(OH)2 was to remove the salts in the prehydrolysates by precipitation.
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Kushwaha D, Srivastava N, Mishra I, Upadhyay SN, Mishra PK. Recent trends in biobutanol production. REV CHEM ENG 2018. [DOI: 10.1515/revce-2017-0041] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Abstract
Finite availability of conventional fossil carbonaceous fuels coupled with increasing pollution due to their overexploitation has necessitated the quest for renewable fuels. Consequently, biomass-derived fuels are gaining importance due to their economic viability and environment-friendly nature. Among various liquid biofuels, biobutanol is being considered as a suitable and sustainable alternative to gasoline. This paper reviews the present state of the preprocessing of the feedstock, biobutanol production through fermentation and separation processes. Low butanol yield and its toxicity are the major bottlenecks. The use of metabolic engineering and integrated fermentation and product recovery techniques has the potential to overcome these challenges. The application of different nanocatalysts to overcome the existing challenges in the biobutanol field is gaining much interest. For the sustainable production of biobutanol, algae, a third-generation feedstock has also been evaluated.
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Affiliation(s)
- Deepika Kushwaha
- Department of Chemical Engineering and Technology, Indian Institute of Technology (BHU) , Varanasi 221005 , India
| | - Neha Srivastava
- Department of Chemical Engineering and Technology, Indian Institute of Technology (BHU) , Varanasi 221005 , India
| | - Ishita Mishra
- Green Brick Eco Solutions, Okha Industrial Area , New Delhi 110020 , India
| | - Siddh Nath Upadhyay
- Department of Chemical Engineering and Technology, Indian Institute of Technology (BHU) , Varanasi 221005 , India
| | - Pradeep Kumar Mishra
- Department of Chemical Engineering and Technology, Indian Institute of Technology (BHU) , Varanasi 221005 , India
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Wu W, Rondon V, Weeks K, Pullammanappallil P, Ingram LO, Shanmugam KT. Phosphoric acid based pretreatment of switchgrass and fermentation of entire slurry to ethanol using a simplified process. BIORESOURCE TECHNOLOGY 2018; 251:171-180. [PMID: 29274857 DOI: 10.1016/j.biortech.2017.12.041] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 12/13/2017] [Accepted: 12/14/2017] [Indexed: 05/21/2023]
Abstract
Switchgrass (Alamo) was pretreated with phosphoric acid (0.75 and 1%, w/w) at three temperatures (160, 175 and 190 °C) and time (5, 7.5 and 10 min) using a steam gun. The slurry after pretreatment was liquefied by enzymes and the released sugars were fermented in a simultaneous saccharification and co-fermentation process to ethanol using ethanologenic Escherichia coli strain SL100. Among the three variables in pretreatment, temperature and time were critical in supporting ethanol titer and yield. Enzyme hydrolysis significantly increased the concentration of furans in slurries, apparently due to release of furans bound to the solids. The highest ethanol titer of 21.2 ± 0.3 g/L ethanol obtained at the pretreatment condition of 190-1-7.5 (temperature-acid concentration-time) and 10% solids loading accounted for 190 ± 2.9 g ethanol/kg of raw switch grass. This converts to 61.7 gallons of ethanol per ton of dry switchgrass, a value that is comparable to other published pretreatment conditions.
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Affiliation(s)
- Wei Wu
- Department of Microbiology and Cell Science, Gainesville, FL 32611, United States; Department of Agricultural and Biological Engineering, Gainesville, FL 32611, United States
| | - Vanessa Rondon
- Department of Microbiology and Cell Science, Gainesville, FL 32611, United States; Stan Mayfield Biorefinery, University of Florida, Gainesville, FL 32611, United States
| | - Kalvin Weeks
- Stan Mayfield Biorefinery, University of Florida, Gainesville, FL 32611, United States
| | | | - Lonnie O Ingram
- Department of Microbiology and Cell Science, Gainesville, FL 32611, United States; Stan Mayfield Biorefinery, University of Florida, Gainesville, FL 32611, United States
| | - K T Shanmugam
- Department of Microbiology and Cell Science, Gainesville, FL 32611, United States.
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Physico-Chemical Conversion of Lignocellulose: Inhibitor Effects and Detoxification Strategies: A Mini Review. Molecules 2018; 23:molecules23020309. [PMID: 29389875 PMCID: PMC6017906 DOI: 10.3390/molecules23020309] [Citation(s) in RCA: 157] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 01/18/2018] [Accepted: 01/30/2018] [Indexed: 11/20/2022] Open
Abstract
A pretreatment of lignocellulosic biomass to produce biofuels, polymers, and other chemicals plays a vital role in the biochemical conversion process toward disrupting the closely associated structures of the cellulose-hemicellulose-lignin molecules. Various pretreatment steps alter the chemical/physical structure of lignocellulosic materials by solubilizing hemicellulose and/or lignin, decreasing the particle sizes of substrate and the crystalline portions of cellulose, and increasing the surface area of biomass. These modifications enhance the hydrolysis of cellulose by increasing accessibilities of acids or enzymes onto the surface of cellulose. However, lignocellulose-derived byproducts, which can inhibit and/or deactivate enzyme and microbial biocatalysts, are formed, including furan derivatives, lignin-derived phenolics, and carboxylic acids. These generation of compounds during pretreatment with inhibitory effects can lead to negative effects on subsequent steps in sugar flat-form processes. A number of physico-chemical pretreatment methods such as steam explosion, ammonia fiber explosion (AFEX), and liquid hot water (LHW) have been suggested and developed for minimizing formation of inhibitory compounds and alleviating their effects on ethanol production processes. This work reviews the physico-chemical pretreatment methods used for various biomass sources, formation of lignocellulose-derived inhibitors, and their contributions to enzymatic hydrolysis and microbial activities. Furthermore, we provide an overview of the current strategies to alleviate inhibitory compounds present in the hydrolysates or slurries.
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Wu G, Xu Z, Jönsson LJ. Profiling of Saccharomyces cerevisiae transcription factors for engineering the resistance of yeast to lignocellulose-derived inhibitors in biomass conversion. Microb Cell Fact 2017; 16:199. [PMID: 29137634 PMCID: PMC5686817 DOI: 10.1186/s12934-017-0811-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 11/04/2017] [Indexed: 11/24/2022] Open
Abstract
Background Yeast transcription factors (TFs) involved in the regulation of multidrug resistance (MDR) were investigated in experiments with deletion mutants, transformants overexpressing synthetic genes encoding TFs, and toxic concentrations of lignocellulose-derived substances added to cultures as complex mixtures or as specific compounds, viz. coniferyl aldehyde, 5-hydroxymethylfurfural, and furfural. Results In the presence of complex mixtures of toxic substances from spruce wood, transformants overexpressing YAP1 and STB5, TFs involved in oxidative stress response, exhibited enhanced relative growth rates amounting to 4.589 ± 0.261 and 1.455 ± 0.185, respectively. Other TFs identified as important for resistance included DAL81, GZF3, LEU3, PUT3, and WAR1. Potential overlapping functions of YAP1 and STB5 were investigated in experiments with permutations of deletions and overexpression of the two genes. YAP1 complemented STB5 with respect to resistance to 5-hydroxymethylfurfural, but had a distinct role with regard to resistance to coniferyl aldehyde as deletion of YAP1 rendered the cell incapable of resisting coniferyl aldehyde even if STB5 was overexpressed. Conclusions We have investigated 30 deletion mutants and eight transformants overexpressing MDR transcription factors with regard to the roles the transcription factors play in the resistance to toxic concentrations of lignocellulose-derived substances. This work provides an overview of the involvement of thirty transcription factors in the resistance to lignocellulose-derived substances, shows distinct and complementary roles played by YAP1 and STB5, and offers directions for the engineering of robust yeast strains for fermentation processes based on lignocellulosic feedstocks.![]() Electronic supplementary material The online version of this article (10.1186/s12934-017-0811-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Guochao Wu
- Department of Chemistry, Umeå University, 901 87, Umeå, Sweden.
| | - Zixiang Xu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Leif J Jönsson
- Department of Chemistry, Umeå University, 901 87, Umeå, Sweden
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Adsorptive detoxification of fermentation inhibitors in acid pretreated liquor using functionalized polymer designed by molecular simulation. Bioprocess Biosyst Eng 2017; 40:1657-1667. [DOI: 10.1007/s00449-017-1821-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 07/25/2017] [Indexed: 11/25/2022]
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34
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Laccases as a Potential Tool for the Efficient Conversion of Lignocellulosic Biomass: A Review. FERMENTATION-BASEL 2017. [DOI: 10.3390/fermentation3020017] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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35
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Detoxification of a Lignocellulosic Waste from a Pulp Mill to Enhance Its Fermentation Prospects. ENERGIES 2017. [DOI: 10.3390/en10030348] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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36
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Production of ethanol from steam exploded triticale straw in a simultaneous saccharification and fermentation process. Process Biochem 2017. [DOI: 10.1016/j.procbio.2016.11.023] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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37
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Biorefinery-Based Lactic Acid Fermentation: Microbial Production of Pure Monomer Product. SYNTHESIS, STRUCTURE AND PROPERTIES OF POLY(LACTIC ACID) 2017. [DOI: 10.1007/12_2016_11] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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38
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Jia H, Shao T, Zhong C, Li H, Jiang M, Zhou H, Wei P. Evaluation of xylitol production using corncob hemicellulosic hydrolysate by combining tetrabutylammonium hydroxide extraction with dilute acid hydrolysis. Carbohydr Polym 2016; 151:676-683. [DOI: 10.1016/j.carbpol.2016.06.013] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 05/26/2016] [Accepted: 06/02/2016] [Indexed: 11/16/2022]
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Coz A, Llano T, Cifrián E, Viguri J, Maican E, Sixta H. Physico-Chemical Alternatives in Lignocellulosic Materials in Relation to the Kind of Component for Fermenting Purposes. MATERIALS 2016; 9:ma9070574. [PMID: 28773700 PMCID: PMC5456911 DOI: 10.3390/ma9070574] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 07/04/2016] [Accepted: 07/08/2016] [Indexed: 11/16/2022]
Abstract
The complete bioconversion of the carbohydrate fraction is of great importance for a lignocellulosic-based biorefinery. However, due to the structure of the lignocellulosic materials, and depending basically on the main parameters within the pretreatment steps, numerous byproducts are generated and they act as inhibitors in the fermentation operations. In this sense, the impact of inhibitory compounds derived from lignocellulosic materials is one of the major challenges for a sustainable biomass-to-biofuel and -bioproduct industry. In order to minimise the negative effects of these compounds, numerous methodologies have been tested including physical, chemical, and biological processes. The main physical and chemical treatments have been studied in this work in relation to the lignocellulosic material and the inhibitor in order to point out the best mechanisms for fermenting purposes. In addition, special attention has been made in the case of lignocellulosic hydrolysates obtained by chemical processes with SO₂, due to the complex matrix of these materials and the increase in these methodologies in future biorefinery markets. Recommendations of different detoxification methods have been given.
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Affiliation(s)
- Alberto Coz
- Green Engineering and Resources, Department of Chemistry and Process and Resource Engineering, University of Cantabria, Avda. Los Castros s/n, Santander 39005, Spain.
| | - Tamara Llano
- Green Engineering and Resources, Department of Chemistry and Process and Resource Engineering, University of Cantabria, Avda. Los Castros s/n, Santander 39005, Spain.
| | - Eva Cifrián
- Green Engineering and Resources, Department of Chemistry and Process and Resource Engineering, University of Cantabria, Avda. Los Castros s/n, Santander 39005, Spain.
| | - Javier Viguri
- Green Engineering and Resources, Department of Chemistry and Process and Resource Engineering, University of Cantabria, Avda. Los Castros s/n, Santander 39005, Spain.
| | - Edmond Maican
- Faculty of Biotechnical Systems Engineering, Politehnica University of Bucharest, 313 Splaiul Independentei, Sector 6, Bucuresti 060042, Romania.
| | - Herbert Sixta
- Department of Forest Products Technology, School of Chemistry, Aalto University, P.O. Box 16300, Aalto FI-00076, Finland.
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40
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Jönsson LJ, Martín C. Pretreatment of lignocellulose: Formation of inhibitory by-products and strategies for minimizing their effects. BIORESOURCE TECHNOLOGY 2016; 199:103-112. [PMID: 26482946 DOI: 10.1016/j.biortech.2015.10.009] [Citation(s) in RCA: 790] [Impact Index Per Article: 98.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 10/05/2015] [Accepted: 10/06/2015] [Indexed: 05/07/2023]
Abstract
Biochemical conversion of lignocellulosic feedstocks to advanced biofuels and other commodities through a sugar-platform process involves a pretreatment step enhancing the susceptibility of the cellulose to enzymatic hydrolysis. A side effect of pretreatment is formation of lignocellulose-derived by-products that inhibit microbial and enzymatic biocatalysts. This review provides an overview of the formation of inhibitory by-products from lignocellulosic feedstocks as a consequence of using different pretreatment methods and feedstocks as well as an overview of different strategies used to alleviate problems with inhibitors. As technologies for biorefining of lignocellulose become mature and are transferred from laboratory environments to industrial contexts, the importance of management of inhibition problems is envisaged to increase as issues that become increasingly relevant will include the possibility to use recalcitrant feedstocks, obtaining high product yields and high productivity, minimizing the charges of enzymes and microorganisms, and using high solids loadings to obtain high product titers.
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Affiliation(s)
- Leif J Jönsson
- Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden.
| | - Carlos Martín
- Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden
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Lin R, Cheng J, Ding L, Song W, Zhou J, Cen K. Sodium borohydride removes aldehyde inhibitors for enhancing biohydrogen fermentation. BIORESOURCE TECHNOLOGY 2015; 197:323-328. [PMID: 26342346 DOI: 10.1016/j.biortech.2015.08.105] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 08/25/2015] [Accepted: 08/26/2015] [Indexed: 06/05/2023]
Abstract
To enhance biohydrogen production from glucose and xylose in the presence of aldehyde inhibitors, reducing agent (i.e., sodium borohydride) was in situ added for effective detoxification. The detoxification efficiencies of furfural (96.7%) and 5-hydroxymethylfurfural (5-HMF, 91.7%) with 30mM NaBH4 were much higher than those of vanillin (77.3%) and syringaldehyde (69.3%). Biohydrogen fermentation was completely inhibited without detoxification, probably because of the consumption of nicotinamide adenine dinucleotide (NADH) by inhibitors reduction (R-CHO+2NADH→R-CH2OH+2NAD(+)). Addition of 30mM NaBH4 provided the reducing power necessary for inhibitors reduction (4R-CHO+NaBH4+2H2O→4R-CH2OH+NaBO2). The recovered reducing power in fermentation resulted in 99.3% recovery of the hydrogen yield and 64.6% recovery of peak production rate. Metabolite production and carbon conversion after detoxification significantly increased to 63.7mM and 81.9%, respectively.
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Affiliation(s)
- Richen Lin
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China
| | - Jun Cheng
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China.
| | - Lingkan Ding
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China
| | - Wenlu Song
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China; Department of Life Science and Engineering, Jining University, Jining 273155, China
| | - Junhu Zhou
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China
| | - Kefa Cen
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China
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Cavka A, Wallenius A, Alriksson B, Nilvebrant NO, Jönsson LJ. Ozone detoxification of steam-pretreated Norway spruce. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:196. [PMID: 26617671 PMCID: PMC4661943 DOI: 10.1186/s13068-015-0388-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 11/16/2015] [Indexed: 05/11/2023]
Abstract
BACKGROUND Pretreatment of lignocellulose for biochemical conversion commonly results in formation of by-products that inhibit microorganisms and cellulolytic enzymes. To make bioconversion processes more efficient, inhibition problems can be alleviated through conditioning. Ozone is currently commercially employed in pulp and paper production for bleaching, as it offers the desirable capability to disrupt unsaturated bonds in lignin through an ionic reaction known as ozonolysis. Ozonolysis is more selective towards lignin than cellulose, for instance, when compared to other oxidative treatment methods, such as Fenton's reagent. Ozone may thus have desirable properties for conditioning of pretreated lignocellulose without concomitant degradation of cellulose or sugars. Ozone treatment of SO2-impregnated steam-pretreated Norway spruce was explored as a potential approach to decrease inhibition of yeast and cellulolytic enzymes. This novel approach was furthermore compared to some of the most effective methods for conditioning of pretreated lignocellulose, i.e., treatment with alkali and sodium dithionite. RESULTS Low dosages of ozone decreased the total contents of phenolics to about half of the initial value and improved the fermentability. Increasing ozone dosages led to almost proportional increase in the contents of total acids, including formic acid, which ultimately led to poor fermentability at higher ozone dosages. The decrease of the contents of furfural and 5-hydroxymethylfurfural was inversely proportional (R (2) > 0.99) to the duration of the ozone treatment, but exhibited no connection with the fermentability. Ozone detoxification was compared with other detoxification methods and was superior to treatment with Fenton's reagent, which exhibited no positive effect on fermentability. However, ozone detoxification was less efficient than treatment with alkali or sodium dithionite. High ozone dosages decreased the inhibition of cellulolytic enzymes as the glucose yield was improved with 13 % compared to that of an untreated control. CONCLUSIONS Low dosages of ozone were beneficial for the fermentation of steam-pretreated Norway spruce, while high dosages decreased the inhibition of cellulolytic enzymes by soluble components in the pretreatment liquid. While clearly of interest for conditioning of lignocellulosic hydrolysates, future challenges include finding conditions that provide beneficial effects both with regard to enzymatic saccharification and microbial fermentation.
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Affiliation(s)
- Adnan Cavka
- />Department of Chemistry, Umeå University, Linnaeus v. 10, 901 87 Umeå, Sweden
| | - Anna Wallenius
- />Department of Chemistry, Umeå University, Linnaeus v. 10, 901 87 Umeå, Sweden
| | | | | | - Leif J. Jönsson
- />Department of Chemistry, Umeå University, Linnaeus v. 10, 901 87 Umeå, Sweden
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Cavka A, Stagge S, Jönsson LJ. Identification of Small Aliphatic Aldehydes in Pretreated Lignocellulosic Feedstocks and Evaluation of Their Inhibitory Effects on Yeast. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2015; 63:9747-9754. [PMID: 26528761 DOI: 10.1021/acs.jafc.5b04803] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Six lignocellulosic hydrolysates produced through acid pretreatment were analyzed for the occurrence of formaldehyde, acetaldehyde, and glycolaldehyde. Acetaldehyde was found in all six (0.3-1.6 mM) and formaldehyde in four (≤ 4.4 mM), whereas glycolaldehyde was not detected. To assess the relevance of these findings, fermentations with yeast and formaldehyde or acetaldehyde were performed in the concentration interval 0.5-10 mM. Formaldehyde already inhibited at 1.0 mM, whereas 5.0 mM acetaldehyde was needed to obtain a clear inhibitory effect. After 24 h of fermentation, 1.5 mM formaldehyde reduced the glucose consumption by 85%, the balanced ethanol yield by 92%, and the volumetric productivity by 91%. The results show that formaldehyde and acetaldehyde are prevalent in pretreated lignocellulose and that formaldehyde in some cases could explain a large part of the inhibitory effects on yeast by lignocellulosic hydrolysates, as three of six hydrolysates contained ≥ 1.9 mM formaldehyde, which was shown to be strongly inhibitory.
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Affiliation(s)
- Adnan Cavka
- Department of Chemistry, Umeå University , SE-901 87 Umeå, Sweden
| | - Stefan Stagge
- Department of Chemistry, Umeå University , SE-901 87 Umeå, Sweden
| | - Leif J Jönsson
- Department of Chemistry, Umeå University , SE-901 87 Umeå, Sweden
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Cavka A, Martín C, Alriksson B, Mörtsell M, Jönsson LJ. Techno-economic evaluation of conditioning with sodium sulfite for bioethanol production from softwood. BIORESOURCE TECHNOLOGY 2015; 196:129-135. [PMID: 26232771 DOI: 10.1016/j.biortech.2015.07.051] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Revised: 07/15/2015] [Accepted: 07/16/2015] [Indexed: 06/04/2023]
Abstract
Conditioning with reducing agents allows alleviation of inhibition of biocatalytic processes by toxic by-products generated during biomass pretreatment, without necessitating the introduction of a separate process step. In this work, conditioning of steam-pretreated spruce with sodium sulfite made it possible to lower the yeast and enzyme dosages in simultaneous saccharification and fermentation (SSF) to 1g/L and 5FPU/g WIS, respectively. Techno-economic evaluation indicates that the cost of sodium sulfite can be offset by benefits resulting from a reduction of either the yeast load by 0.68g/L or the enzyme load by 1FPU/g WIS. As those thresholds were surpassed, inclusion of conditioning can be justified. Another potential benefit results from shortening the SSF time, which would allow reducing the bioreactor volume and result in capital savings. Sodium sulfite conditioning emerges as an opportunity to lower the financial uncertainty and compensate the overall investment risk for commercializing a softwood-to-ethanol process.
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Affiliation(s)
- Adnan Cavka
- Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden
| | - Carlos Martín
- Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden.
| | | | | | - Leif J Jönsson
- Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden
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Matsakas L, Rova U, Christakopoulos P. Sequential parametric optimization of methane production from different sources of forest raw material. Front Microbiol 2015; 6:1163. [PMID: 26539186 PMCID: PMC4611140 DOI: 10.3389/fmicb.2015.01163] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 10/06/2015] [Indexed: 11/13/2022] Open
Abstract
The increase in environmental problems and the shortage of fossil fuels have led to the need for action in the development of sustainable and renewable fuels. Methane is produced through anaerobic digestion of organic materials and is a biofuel with very promising characteristics. The success in using methane as a biofuel has resulted in the operation of several commercial-scale plants and the need to exploit novel materials to be used. Forest biomass can serve as an excellent candidate for use as raw material for anaerobic digestion. During this work, both hardwood and softwood species-which are representative of the forests of Sweden-were used for the production of methane. Initially, when untreated forest materials were used for the anaerobic digestion, the yields obtained were very low, even with the addition of enzymes, reaching a maximum of only 40 mL CH4/g VS when birch was used. When hydrothermal pretreatment was applied, the enzymatic digestibility improved up to 6.7 times relative to that without pretreatment, and the yield of methane reached up to 254 mL CH4/g VS. Then the effect of chemical/enzymatic detoxification was examined, where laccase treatment improved the methane yield from the more harshly pretreated materials while it had no effect on the more mildly pretreated material. Finally, addition of cellulolytic enzymes during the digestion improved the methane yields from spruce and pine, whereas for birch separate saccharification was more beneficial. To achieve high yields in spruce 30 filter paper units (FPU)/g was necessary, whereas 15 FPU/g was enough when pine and birch were used. During this work, the highest methane yields obtained from pine and birch were 179.9 mL CH4/g VS and 304.8 mL CH4/g VS, respectively. For mildly and severely pretreated spruce, the methane yields reached 259.4 mL CH4/g VS and 276.3 mL CH4/g VS, respectively. We have shown that forest material can serve as raw material for efficient production of methane. The initially low yields from the untreated materials were significantly improved by the introduction of a hydrothermal pretreatment. Moreover, enzymatic detoxification was beneficial, but mainly for severely pretreated materials. Finally, enzymatic saccharification increased the methane yields even further.
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Affiliation(s)
- Leonidas Matsakas
- Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology Luleå, Sweden
| | - Ulrika Rova
- Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology Luleå, Sweden
| | - Paul Christakopoulos
- Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology Luleå, Sweden
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Agrawal R, Satlewal A, Gaur R, Mathur A, Kumar R, Gupta RP, Tuli DK. Pilot scale pretreatment of wheat straw and comparative evaluation of commercial enzyme preparations for biomass saccharification and fermentation. Biochem Eng J 2015. [DOI: 10.1016/j.bej.2015.02.018] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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47
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Weissgram M, Gstöttner J, Lorantfy B, Tenhaken R, Herwig C, Weber HK. Generation of PHB from Spent Sulfite Liquor Using Halophilic Microorganisms. Microorganisms 2015; 3:268-89. [PMID: 27682089 PMCID: PMC5023234 DOI: 10.3390/microorganisms3020268] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 04/28/2015] [Accepted: 05/20/2015] [Indexed: 12/03/2022] Open
Abstract
Halophilic microorganisms thrive at elevated concentrations of sodium chloride up to saturation and are capable of growing on a wide variety of carbon sources like various organic acids, hexose and also pentose sugars. Hence, the biotechnological application of these microorganisms can cover many aspects, such as the treatment of hypersaline waste streams of different origin. Due to the fact that the high osmotic pressure of hypersaline environments reduces the risk of contamination, the capacity for cost-effective non-sterile cultivation can make extreme halophilic microorganisms potentially valuable organisms for biotechnological applications. In this contribution, the stepwise use of screening approaches, employing design of experiment (DoE) on model media and subsequently using industrial waste as substrate have been implemented to investigate the applicability of halophiles to generate PHB from the industrial waste stream spent sulfite liquor (SSL). The production of PHB on model media as well as dilutions of industrial substrate in a complex medium has been screened for by fluorescence microscopy using Nile Blue staining. Screening was used to investigate the ability of halophilic microorganisms to withstand the inhibiting substances of the waste stream without negatively affecting PHB production. It could be shown that neither single inhibiting substances nor a mixture thereof inhibited growth in the investigated range, hence, leaving the question on the inhibiting mechanisms open. However, it could be demonstrated that some haloarchaea and halophilic bacteria are able to produce PHB when cultivated on 3.3% w/w dry matter spent sulfite liquor, whereas H. halophila was even able to thrive on 6.6% w/w dry matter spent sulfite liquor and still produce PHB.
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Affiliation(s)
- Michaela Weissgram
- Kompetenzzentrum Holz GmbH, Altenbergerstraße 69, Linz 4040, Austria.
- Institute of Chemical Engineering, Research Area Biochemical Engineering, Vienna University of Technology, Gumpendorferstraße 1a, Vienna 1060, Austria.
| | - Janina Gstöttner
- Kompetenzzentrum Holz GmbH, Altenbergerstraße 69, Linz 4040, Austria.
- Department of Cell Biology, University of Salzburg, Hellbrunnerstr 34, Salzburg 5020, Austria.
| | - Bettina Lorantfy
- Institute of Chemical Engineering, Research Area Biochemical Engineering, Vienna University of Technology, Gumpendorferstraße 1a, Vienna 1060, Austria.
| | - Raimund Tenhaken
- Department of Cell Biology, University of Salzburg, Hellbrunnerstr 34, Salzburg 5020, Austria.
| | - Christoph Herwig
- Institute of Chemical Engineering, Research Area Biochemical Engineering, Vienna University of Technology, Gumpendorferstraße 1a, Vienna 1060, Austria.
| | - Hedda K Weber
- Kompetenzzentrum Holz GmbH, Altenbergerstraße 69, Linz 4040, Austria.
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Reginatto V, Antônio RV. Fermentative hydrogen production from agroindustrial lignocellulosic substrates. Braz J Microbiol 2015; 46:323-35. [PMID: 26273246 PMCID: PMC4507523 DOI: 10.1590/s1517-838246220140111] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 10/09/2014] [Indexed: 11/23/2022] Open
Abstract
To achieve economically competitive biological hydrogen production, it is crucial
to consider inexpensive materials such as lignocellulosic substrate residues
derived from agroindustrial activities. It is possible to use (1)
lignocellulosic materials without any type of pretreatment, (2) lignocellulosic
materials after a pretreatment step, and (3) lignocellulosic materials
hydrolysates originating from a pretreatment step followed by enzymatic
hydrolysis. According to the current literature data on fermentative
H2 production presented in this review, thermophilic conditions
produce H2 in yields approximately 75% higher than those obtained in
mesophilic conditions using untreated lignocellulosic substrates. The average
H2 production from pretreated material is 3.17 ± 1.79 mmol of
H2/g of substrate, which is approximately 50% higher compared
with the average yield achieved using untreated materials (2.17 ± 1.84 mmol of
H2/g of substrate). Biological pretreatment affords the highest
average yield 4.54 ± 1.78 mmol of H2/g of substrate compared with the
acid and basic pretreatment - average yields of 2.94 ± 1.85 and 2.41 ± 1.52 mmol
of H2/g of substrate, respectively. The average H2 yield
from hydrolysates, obtained from a pretreatment step and enzymatic hydrolysis
(3.78 ± 1.92 mmol of H2/g), was lower compared with the yield of
substrates pretreated by biological methods only, demonstrating that it is
important to avoid the formation of inhibitors generated by chemical
pretreatments. Based on this review, exploring other microorganisms and
optimizing the pretreatment and hydrolysis conditions can make the use of
lignocellulosic substrates a sustainable way to produce H2.
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Affiliation(s)
- Valeria Reginatto
- Universidade de São Paulo, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil, Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
| | - Regina Vasconcellos Antônio
- Universidade Federal de Santa Catarina, Universidade Federal de Santa Catarina, Araranguá, SC, Brasil, Universidade Federal de Santa Catarina, Araranguá, SC, Brazil
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Lee KM, Kim KY, Choi O, Woo HM, Kim Y, Han SO, Sang BI, Um Y. In situ detoxification of lignocellulosic hydrolysate using a surfactant for butyric acid production by Clostridium tyrobutyricum ATCC 25755. Process Biochem 2015. [DOI: 10.1016/j.procbio.2015.01.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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50
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Geddes R, Shanmugam KT, Ingram LO. Combining treatments to improve the fermentation of sugarcane bagasse hydrolysates by ethanologenic Escherichia coli LY180. BIORESOURCE TECHNOLOGY 2015; 189:15-22. [PMID: 25864026 DOI: 10.1016/j.biortech.2015.03.141] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 03/27/2015] [Accepted: 03/29/2015] [Indexed: 06/04/2023]
Abstract
Inhibitory side products from dilute acid pretreatment is a major challenge for conversion of lignocellulose into ethanol. Six strategies to detoxify sugarcane hydrolysates were investigated alone, and in combinations (vacuum evaporation of volatiles, high pH treatment with ammonia, laccase, bisulfite, microaeration, and inoculum size). High pH was the most beneficial single treatment, increasing the minimum inhibitory concentration (measured by ethanol production) from 15% (control) to 70% hydrolysate. Combining treatments provided incremental improvements, consistent with different modes of action and multiple inhibitory compounds. Screening toxicity using tube cultures proved to be an excellent predictor of relative performance in pH-controlled fermenters. A combination of treatments (vacuum evaporation, laccase, high pH, bisulfite, microaeration) completely eliminated all inhibitory activity present in hydrolysate. With this combination, fermentation of hemicellulose sugars (90% hydrolysate) to ethanol was complete within 48 h, identical to the fermentation of laboratory xylose (50 g/L) in AM1 mineral salts medium (without hydrolysate).
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Affiliation(s)
- Ryan Geddes
- Department of Microbiology & Cell Science, University of Florida, Box 110700, Gainesville, FL 32611, USA.
| | - Keelnatham T Shanmugam
- Department of Microbiology & Cell Science, University of Florida, Box 110700, Gainesville, FL 32611, USA.
| | - Lonnie O Ingram
- Department of Microbiology & Cell Science, University of Florida, Box 110700, Gainesville, FL 32611, USA.
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