1
|
High-throughput screening of environmental polysaccharide-degrading bacteria using biomass containment and complex insoluble substrates. Appl Microbiol Biotechnol 2020; 104:3379-3389. [PMID: 32114675 PMCID: PMC7089899 DOI: 10.1007/s00253-020-10469-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 12/12/2019] [Accepted: 02/12/2020] [Indexed: 11/08/2022]
Abstract
Carbohydrate degradation by microbes plays an important role in global nutrient cycling, human nutrition, and biotechnological applications. Studies that focus on the degradation of complex recalcitrant polysaccharides are challenging because of the insolubility of these substrates as found in their natural contexts. Specifically, current methods to examine carbohydrate-based biomass degradation using bacterial strains or purified enzymes are not compatible with high-throughput screening using complex insoluble materials. In this report, we developed a small 3D printed filter device that fits inside a microplate well that allows for the free movement of bacterial cells, media, and enzymes while containing insoluble biomass. These devices do not interfere with standard microplate readers and can be used for both short- (24–48 h) and long-duration (> 100 h) experiments using complex insoluble substrates. These devices were used to quantitatively screen in a high-throughput manner environmental isolates for their ability to grow using lignocellulose or rice grains as a sole nutrient source. Additionally, we determined that the microplate-based containment devices are compatible with existing enzymatic assays to measure activity against insoluble biomass. Overall, these microplate containment devices provide a platform to study the degradation of complex insoluble materials in a high-throughput manner and have the potential to help uncover ecologically important aspects of bacterial metabolism as well as to accelerate biotechnological innovation.
Collapse
|
2
|
Takenaka M, Lee JM, Kahar P, Ogino C, Kondo A. Efficient and Supplementary Enzyme Cocktail from Actinobacteria and Plant Biomass Induction. Biotechnol J 2018; 14:e1700744. [PMID: 29981210 DOI: 10.1002/biot.201700744] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 06/28/2018] [Indexed: 11/08/2022]
Abstract
Actinobacteria plays a key role in the cycling of organic matter in soils. They secret biomass-degrading enzymes that allow it to produce the unique metabolites that originate in plant biomass. Although past studies have focused on these unique metabolites, a large-scale screening of Actinobacteria is yet to be reported to focus on their biomass-degrading ability. In the present study, a rapid and simple method is constructed for a large-scale screening, and the novel resources that form the plant biomass-degrading enzyme cocktail are identified from 850 isolates of Actinobacteria. As a result, Nonomuraea fastidiosa secretes a biomass degrading enzyme cocktail with the highest enzyme titer, although cellulase activities are lower than a commercially available enzyme. So the rich accessory enzymes are suggested to contribute to the high enzyme titer for a pretreated bagasse with a synergistic effect. Additionally, an optimized cultivation method of biomass induction caused to produce the improved enzyme cocktail indicated strong enzyme titers and a strong synergistic effect. Therefore, the novel enzyme cocktails are selected via the optimized method for large-scale screening, and then the enzyme cocktail can be improved via the optimized production with biomass-induction.
Collapse
Affiliation(s)
- Musashi Takenaka
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, Rokkodaicho 1-1, 657-8501 Kobe, Japan
| | - Jae M Lee
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, Rokkodaicho 1-1, 657-8501 Kobe, Japan
| | - Prihardi Kahar
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, Rokkodaicho 1-1, 657-8501 Kobe, Japan
| | - Chiaki Ogino
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, Rokkodaicho 1-1, 657-8501 Kobe, Japan
| | - Akihiko Kondo
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, Rokkodaicho 1-1, 657-8501 Kobe, Japan
| |
Collapse
|
3
|
Wei X, Wu Q, Zhang J, Zhang Y, Guo W, Chen M, Gu Q, Cai Z, Lu M. Synthesis of precipitating chromogenic/fluorogenic β-glucosidase/β-galactosidase substrates by a new method and their application in the visual detection of foodborne pathogenic bacteria. Chem Commun (Camb) 2017; 53:103-106. [PMID: 27878149 DOI: 10.1039/c6cc07522c] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We developed a new efficient method for the synthesis of important indoxyl glycoside substrates for β-glucosidase and β-galactosidase by using 1-acetylindol-3-ones as intermediates. This method was used to synthesise novel precipitating fluorogenic substrates for β-glucosidase based on 2-(benzothiazol-2'-yl)-phenols. We also assessed the application of these substrates in the detection of foodborne pathogenic bacteria.
Collapse
Affiliation(s)
- Xianhu Wei
- Guangzhou Institute of Chemistry, Chinese Academy of Sciences, Guangzhou 510650, China and Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou 510070, China. and University of Chinese Academy of Sciences, Beijing 100039, China
| | - Qingping Wu
- Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou 510070, China.
| | - Jumei Zhang
- Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou 510070, China.
| | - Youxiong Zhang
- Guangzhou Institute of Chemistry, Chinese Academy of Sciences, Guangzhou 510650, China and Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou 510070, China. and University of Chinese Academy of Sciences, Beijing 100039, China
| | - Weipeng Guo
- Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou 510070, China.
| | - Moutong Chen
- Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou 510070, China.
| | - Qihui Gu
- Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangzhou 510070, China. and School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China
| | - Zhihe Cai
- Guangdong Huankai Microbial Sci. & Tech. Co., Ltd, Guangzhou 510663, China
| | - Mianfei Lu
- Guangdong Huankai Microbial Sci. & Tech. Co., Ltd, Guangzhou 510663, China
| |
Collapse
|
4
|
Malinowska KH, Verdorfer T, Meinhold A, Milles LF, Funk V, Gaub HE, Nash MA. Redox-initiated hydrogel system for detection and real-time imaging of cellulolytic enzyme activity. CHEMSUSCHEM 2014; 7:2825-2831. [PMID: 25116339 DOI: 10.1002/cssc.201402428] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 06/12/2014] [Indexed: 06/03/2023]
Abstract
Understanding the process of biomass degradation by cellulolytic enzymes is of urgent importance for biofuel and chemical production. Optimizing pretreatment conditions and improving enzyme formulations both require assays to quantify saccharification products on solid substrates. Typically, such assays are performed using freely diffusing fluorophores or dyes that measure reducing polysaccharide chain ends. These methods have thus far not allowed spatial localization of hydrolysis activity to specific substrate locations with identifiable morphological features. Here we describe a hydrogel reagent signaling (HyReS) system that amplifies saccharification products and initiates crosslinking of a hydrogel that localizes to locations of cellulose hydrolysis, allowing for imaging of the degradation process in real time. Optical detection of the gel in a rapid parallel format on synthetic and natural pretreated solid substrates was used to quantify activity of T. emersonii and T. reesei enzyme cocktails. When combined with total internal reflection fluorescence microscopy and AFM imaging, the reagent system provided a means to visualize enzyme activity in real-time with high spatial resolution (<2 μm). These results demonstrate the versatility of the HyReS system in detecting cellulolytic enzyme activity and suggest new opportunities in real-time chemical imaging of biomass depolymerization.
Collapse
Affiliation(s)
- Klara H Malinowska
- Lehrstuhl für Angewandte Physik and Center for Nanoscience, Ludwig-Maximilians-Universität, Amalienstrasse 54, 80799 Munich (Germany)
| | | | | | | | | | | | | |
Collapse
|
5
|
Poggi-Parodi D, Bidard F, Pirayre A, Portnoy T, Blugeon C, Seiboth B, Kubicek CP, Le Crom S, Margeot A. Kinetic transcriptome analysis reveals an essentially intact induction system in a cellulase hyper-producer Trichoderma reesei strain. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:173. [PMID: 25550711 PMCID: PMC4279801 DOI: 10.1186/s13068-014-0173-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 11/18/2014] [Indexed: 05/15/2023]
Abstract
BACKGROUND The filamentous fungus Trichoderma reesei is the main industrial cellulolytic enzyme producer. Several strains have been developed in the past using random mutagenesis, and despite impressive performance enhancements, the pressure for low-cost cellulases has stimulated continuous research in the field. In this context, comparative study of the lower and higher producer strains obtained through random mutagenesis using systems biology tools (genome and transcriptome sequencing) can shed light on the mechanisms of cellulase production and help identify genes linked to performance. Previously, our group published comparative genome sequencing of the lower and higher producer strains NG 14 and RUT C30. In this follow-up work, we examine how these mutations affect phenotype as regards the transcriptome and cultivation behaviour. RESULTS We performed kinetic transcriptome analysis of the NG 14 and RUT C30 strains of early enzyme production induced by lactose using bioreactor cultivations close to an industrial cultivation regime. RUT C30 exhibited both earlier onset of protein production (3 h) and higher steady-state productivity. A rather small number of genes compared to previous studies were regulated (568), most of them being specific to the NG 14 strain (319). Clustering analysis highlighted similar behaviour for some functional categories and allowed us to distinguish between induction-related genes and productivity-related genes. Cross-comparison of our transcriptome data with previously identified mutations revealed that most genes from our dataset have not been mutated. Interestingly, the few mutated genes belong to the same clusters, suggesting that these clusters contain genes playing a role in strain performance. CONCLUSIONS This is the first kinetic analysis of a transcriptomic study carried out under conditions approaching industrial ones with two related strains of T. reesei showing distinctive cultivation behaviour. Our study sheds some light on some of the events occurring in these strains following induction by lactose. The fact that few regulated genes have been affected by mutagenesis suggests that the induction mechanism is essentially intact compared to that for the wild-type isolate QM6a and might be engineered for further improvement of T. reesei. Genes from two specific clusters might be potential targets for such genetic engineering.
Collapse
Affiliation(s)
- Dante Poggi-Parodi
- />IFP Energies nouvelles, 1-4 avenue de Bois-Préau, 92852 Rueil-Malmaison, France
- />Sorbonne Universités, UPMC Univ Paris 06, Institut de Biologie Paris-Seine (IBPS), F-75005 Paris, France
| | - Frédérique Bidard
- />IFP Energies nouvelles, 1-4 avenue de Bois-Préau, 92852 Rueil-Malmaison, France
| | - Aurélie Pirayre
- />IFP Energies nouvelles, 1-4 avenue de Bois-Préau, 92852 Rueil-Malmaison, France
| | - Thomas Portnoy
- />IFP Energies nouvelles, 1-4 avenue de Bois-Préau, 92852 Rueil-Malmaison, France
- />Ecole Normale Supérieure, Institut de Biologie de l’ENS, IBENS, Plateforme Génomique, Paris, F-75005 France
- />Ecole Normale Supérieure, Institut de Biologie de l’ENS, IBENS, Inserm, U1024, Paris, F-75005 France
- />Ecole Normale Supérieure, Institut de Biologie de l’ENS, IBENS, CNRS, UMR 8197, Paris, F-75005 France
| | - Corinne Blugeon
- />Ecole Normale Supérieure, Institut de Biologie de l’ENS, IBENS, Plateforme Génomique, Paris, F-75005 France
- />Ecole Normale Supérieure, Institut de Biologie de l’ENS, IBENS, Inserm, U1024, Paris, F-75005 France
- />Ecole Normale Supérieure, Institut de Biologie de l’ENS, IBENS, CNRS, UMR 8197, Paris, F-75005 France
| | - Bernhard Seiboth
- />Research Division Biotechnology and Microbiology, Institute of Chemical Engineering, Technische Universität Wien, Getreidemarkt 9/166, A- 1060 Vienna, Austria
| | | | - Stéphane Le Crom
- />Sorbonne Universités, UPMC Univ Paris 06, Institut de Biologie Paris-Seine (IBPS), F-75005 Paris, France
- />Ecole Normale Supérieure, Institut de Biologie de l’ENS, IBENS, Plateforme Génomique, Paris, F-75005 France
- />Ecole Normale Supérieure, Institut de Biologie de l’ENS, IBENS, Inserm, U1024, Paris, F-75005 France
- />Ecole Normale Supérieure, Institut de Biologie de l’ENS, IBENS, CNRS, UMR 8197, Paris, F-75005 France
| | - Antoine Margeot
- />IFP Energies nouvelles, 1-4 avenue de Bois-Préau, 92852 Rueil-Malmaison, France
| |
Collapse
|
6
|
Woo HL, Hazen TC, Simmons BA, DeAngelis KM. Enzyme activities of aerobic lignocellulolytic bacteria isolated from wet tropical forest soils. Syst Appl Microbiol 2013; 37:60-7. [PMID: 24238986 DOI: 10.1016/j.syapm.2013.10.001] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 10/09/2013] [Accepted: 10/15/2013] [Indexed: 10/26/2022]
Abstract
Lignocellulolytic bacteria have promised to be a fruitful source of new enzymes for next-generation lignocellulosic biofuel production. Puerto Rican tropical forest soils were targeted because the resident microbes decompose biomass quickly and to near-completion. Isolates were initially screened based on growth on cellulose or lignin in minimal media. 75 Isolates were further tested for the following lignocellulolytic enzyme activities: phenol oxidase, peroxidase, β-d-glucosidase, cellobiohydrolase, β-xylopyranosidase, chitinase, CMCase, and xylanase. Cellulose-derived isolates possessed elevated β-d-glucosidase, CMCase, and cellobiohydrolase activity but depressed phenol oxidase and peroxidase activity, while the contrary was true of lignin isolates, suggesting that these bacteria are specialized to subsist on cellulose or lignin. Cellobiohydrolase and phenol oxidase activity rates could classify lignin and cellulose isolates with 61% accuracy, which demonstrates the utility of model degradation assays. Based on 16S rRNA gene sequencing, all isolates belonged to phyla dominant in the Puerto Rican soils, Proteobacteria, Firmicutes, and Actinobacteria, suggesting that many dominant taxa are capable of the rapid lignocellulose degradation characteristic of these soils. The isolated genera Aquitalea, Bacillus, Burkholderia, Cupriavidus, Gordonia, and Paenibacillus represent rarely or never before studied lignolytic or cellulolytic species and were undetected by metagenomic analysis of the soils. The study revealed a relationship between phylogeny and lignocellulose-degrading potential, supported by Kruskal-Wallis statistics which showed that enzyme activities of cultivated phyla and genera were different enough to be considered representatives of distinct populations. This can better inform future experiments and enzyme discovery efforts.
Collapse
Affiliation(s)
- Hannah L Woo
- Microbial Communities Group, Deconstruction Division, Joint BioEnergy Institute, United States; Physical Biosciences Division, Lawrence Berkeley National Laboratory, United States; Department of Civil & Environmental Engineering, The University of Tennessee, United States
| | - Terry C Hazen
- Microbial Communities Group, Deconstruction Division, Joint BioEnergy Institute, United States; Earth Sciences Division, Ecology Department, Lawrence Berkeley National Laboratory, United States; Department of Civil & Environmental Engineering, The University of Tennessee, United States; Department of Microbiology, The University of Tennessee, United States; Department of Earth & Planetary Sciences, The University of Tennessee, United States; Biosciences Division, Oak Ridge National Laboratory, United States
| | - Blake A Simmons
- Microbial Communities Group, Deconstruction Division, Joint BioEnergy Institute, United States; Biomass Science and Conversion Technology Department, Sandia National Laboratories, United States
| | - Kristen M DeAngelis
- Microbial Communities Group, Deconstruction Division, Joint BioEnergy Institute, United States; Earth Sciences Division, Ecology Department, Lawrence Berkeley National Laboratory, United States; Microbiology Department, University of Massachusetts Amherst, United States.
| |
Collapse
|
7
|
Medium-throughput profiling method for screening polysaccharide-degrading enzymes in complex bacterial extracts. J Microbiol Methods 2012; 89:222-9. [PMID: 22465222 DOI: 10.1016/j.mimet.2012.03.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 03/06/2012] [Accepted: 03/06/2012] [Indexed: 01/26/2023]
Abstract
Polysaccharides are the most abundant and the most diverse renewable materials found on earth. Due to the stereochemical variability of carbohydrates, polysaccharide-degrading enzymes - i.e. glycoside hydrolases and polysaccharide lyases - are essential tools for resolving the structure of these complex macromolecules. The exponential increase of genomic and metagenomic data contrasts sharply with the low number of proteins that have ascribed functions. To help fill this gap, we designed and implemented a medium-throughput profiling method to screen for polysaccharide-degrading enzymes in crude bacterial extracts. Our strategy was based on a series of filtrations, which are absolutely necessary to eliminate any reducing sugars not directly generated by enzyme degradation. In contrast with other protocols already available in the literature, our method can be applied to any panel of polysaccharides having known and unknown structures because no chemical modifications are required. We applied this approach to screen for enzymes that occur in Pseudoalteromonas carrageenovora grown in two culture conditions.
Collapse
|
8
|
Gardner JG, Zeitler LA, Wigstrom WJS, Engel KC, Keating DH. A high-throughput solid phase screening method for identification of lignocellulose-degrading bacteria from environmental isolates. Biotechnol Lett 2011; 34:81-9. [PMID: 21904949 DOI: 10.1007/s10529-011-0742-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Accepted: 08/24/2011] [Indexed: 11/25/2022]
Abstract
The development of cost-effective biofuels will require improvements in the efficiency of biomass deconstruction, a process typically carried out by lignocellulose-degrading enzymes. Environmental microbes represent an abundant and diverse source of lignocelluloses-degrading enzymes for use in biotechnology. However, identification of microorganisms that possess these enzymes has been slowed by a lack of rapid screening methodologies, particularly those that utilize native lignocellulosic substrates. In this report, we describe a new, solid-phase screening system for the identification of microbes capable of lignocellulose degradation. The critical component of this screening system is the use of acrylamide, instead of agar, as the solidifying agent. Our results show that this screening method allows for the identification of Gram-positive and Gram-negative bacteria that possess cellulose and hemicellulose degrading activities from environmental isolates.
Collapse
Affiliation(s)
- Jeffrey G Gardner
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, 3554 Microbial Sciences Building, 1550 Linden Dr., Madison, WI 53706, USA
| | | | | | | | | |
Collapse
|
9
|
Yin LJ, Huang PS, Lin HH. Isolation of cellulase-producing bacteria and characterization of the cellulase from the isolated bacterium Cellulomonas sp. YJ5. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:9833-9837. [PMID: 20687562 DOI: 10.1021/jf1019104] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A cellulase-producing bacterium was isolated from soil and identified as Cellulomonas sp. YJ5. Maximal cellulase activity was obtained after 48 h of incubation at 30 degrees C in a medium containing 1.0% carboxymethyl cellulose (CMC), 1.0% algae powder, 1.0% peptone, 0.24% (NH4)2SO4, 0.20% K2HPO4, and 0.03% MgSO(4).7H2O. The cellulase was purified after Sephacryl S-100 chromatography twice with a recovery of 27.9% and purification fold of 17.5. It was, with N-terminal amino acids of AGTKTPVAK, stable at pH 7.5-10.5 and 20-50 degrees C with optimal pH and temperature of 7.0 and 60 degrees C, respectively. Cu2+, Fe2+, Hg2+, Cr3+, and SDS highly inhibited, but cysteine and beta-mercaptoethanol activated, its activity. Substrate specificity indicated it to be an endo-beta-1,4-glucanase.
Collapse
Affiliation(s)
- Li-Jung Yin
- Department of Sea Food Science, National Kaohsiung Marine University, No. 142 Hai-Chuan Road, Nan-Tzu, Kaohsiung 81143, Taiwan.
| | | | | |
Collapse
|
10
|
Maki M, Leung KT, Qin W. The prospects of cellulase-producing bacteria for the bioconversion of lignocellulosic biomass. Int J Biol Sci 2009; 5:500-16. [PMID: 19680472 PMCID: PMC2726447 DOI: 10.7150/ijbs.5.500] [Citation(s) in RCA: 261] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Accepted: 07/21/2009] [Indexed: 11/05/2022] Open
Abstract
Lignocellulosic biomass is a renewable and abundant resource with great potential for bioconversion to value-added bioproducts. However, the biorefining process remains economically unfeasible due to a lack of biocatalysts that can overcome costly hurdles such as cooling from high temperature, pumping of oxygen/stirring, and, neutralization from acidic or basic pH. The extreme environmental resistance of bacteria permits screening and isolation of novel cellulases to help overcome these challenges. Rapid, efficient cellulase screening techniques, using cellulase assays and metagenomic libraries, are a must. Rare cellulases with activities on soluble and crystalline cellulose have been isolated from strains of Paenibacillus and Bacillus and shown to have high thermostability and/or activity over a wide pH spectrum. While novel cellulases from strains like Cellulomonas flavigena and Terendinibacter turnerae, produce multifunctional cellulases with broader substrate utilization. These enzymes offer a framework for enhancement of cellulases including: specific activity, thermalstability, or end-product inhibition. In addition, anaerobic bacteria like the clostridia offer potential due to species capable of producing compound multienzyme complexes called cellulosomes. Cellulosomes provide synergy and close proximity of enzymes to substrate, increasing activity towards crystalline cellulose. This has lead to the construction of designer cellulosomes enhanced for specific substrate activity. Furthermore, cellulosome-producing Clostridium thermocellum and its ability to ferment sugars to ethanol; its amenability to co-culture and, recent advances in genetic engineering, offer a promising future in biofuels. The exploitation of bacteria in the search for improved enzymes or strategies provides a means to upgrade feasibility for lignocellulosic biomass conversion, ultimately providing means to a 'greener' technology.
Collapse
Affiliation(s)
- Miranda Maki
- Biorefining Research Initiative, Lakehead University, Thunder Bay, Ontario, Canada
| | | | | |
Collapse
|