Mixture optimization of six core glycosyl hydrolases for maximizing saccharification of ammonia fiber expansion (AFEX) pretreated corn stover

Gao, Dahai; Chundawat, Shishir P. S.; Krishnan, Chandraraj; Balan, Venkatesh; Dale, Bruce E.

doi:10.1016/j.biortech.2009.10.056

Cited by 191 publications

(200 citation statements)

References 31 publications

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“…Although both of the endocellulases were found to have significant activity on pNPC, their CMC activity was slightly lower or comparable to EG I. LX1 and LX2 were found to have much higher xylanase activity than EG I, though earlier work has reported another Geobacillus xylanase (with 88% similarity to LX1) to have lost 40-60% activity at pH 5 [31]. Recent work with a fungal endo-xylanase isolated from Trichoderma has shown that the Geobacillus enzyme has three-to fivefold higher activity on oat spelt xylan under identical conditions [28]. LβX was found to have high xylosidase activity but poor α-arabinofuranosidase activity, comparable to what has been reported earlier [32].…”

Section: Specific Activities Of Bacterial and Fungal Enzymesmentioning

confidence: 99%

“…Cellulases (CBH I, CBH II, and EG I) and βG were purified from Spezyme CP (Genencor, Rochester, NY, USA) and Novo 188 (Novozyme, Davis, CA, USA), respectively. The purification methodology has been described in our previous work [28].…”

Section: Enzyme Expression and Purificationmentioning

confidence: 99%

“…This iterative method allows one to determine the most efficient enzyme/enzyme mixtures that have high activity on pretreated lignocellulosic biomass and avoid the pitfall of screening individual enzymes on unrealistic substrates (e.g., CMC, pNP-glycosides) [29]. Once a minimal enzyme mixture has been defined, it should be possible to further reduce enzyme dosage by optimizing the relative ratios of the enzymes in the mixture to maximize glucan and xylan digestibility [28].…”

Section: Strategy For Enzyme Screening On Realistic Lignocellulosic Smentioning

confidence: 99%

“…Bacterial LX1 and LX2 together were always more than 5% of total enzyme loading while bacterial LβX was greater than 1%. All of the above constraints were based on the fact that cellobiohydrolase, endoglucanase, β-glucosidase, endoxylanase, and β-xylosidase are indispensible for an efficient enzyme cocktail [28]. Deconstruction of crystalline cellulose is the major limiting step towards complete hydrolysis, hence requiring significant amount of cellulase loading.…”

Section: Enzyme Mixture Optimizationmentioning

confidence: 99%

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Strategy for Identification of Novel Fungal and Bacterial Glycosyl Hydrolase Hybrid Mixtures that can Efficiently Saccharify Pretreated Lignocellulosic Biomass

et al. 2010

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A rational four-step strategy to identify novel bacterial glycosyl hydrolases (GH), in combination with various fungal enzymes, was applied in order to develop tailored enzyme cocktails to efficiently hydrolyze pretreated lignocellulosic biomass. The fungal cellulases include cellobiohydrolase I (CBH I; GH family 7A), cellobiohydrolase II (CBH II; GH family 6A), endoglucanase I (EG I; GH family 7B), and β-glucosidase (βG; GH family 3). Bacterial endocellulases (LC1 and LC2; GH family 5), β-glucosidase (LβG; GH family 1), endoxylanases (LX1 and LX2; GH family 10), and β-xylosidase (LβX; GH family 52) from multiple sources were cloned, expressed, and purified. Enzymatic hydrolysis for varying enzyme combinations was carried out on ammonia fiber expansion (AFEX)-treated corn stover at three total protein loadings (i.e., 33, 16.5, and 11 mg enzyme/g glucan). The optimal mass ratio of enzymes necessary to maximize both glucan and xylan yields was determined using a suitable design of experiments. The optimal hybrid enzyme mixtures contained fungal cellulases (78% of total protein loading), which included CBH I (loading ranging between 9-51% of total enzyme), CBH II (9-51%), EG I (10-50%), and bacterial hemicellulases (22% of total protein loading) comprising of LX1 (13%) and LβX (9%). The hybrid mixture was effective at 50°C, pH 4.5 to maximize saccharification of AFEX-treated corn stover resulting in 95% glucan and 65% xylan conversion. This strategy of screening novel enzyme mixtures on pretreated lignocellulose would ultimately lead to the development of tailored enzyme cocktails that can hydrolyze plant cell walls efficiently and economically to produce cellulosic ethanol.

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Section: Specific Activities Of Bacterial and Fungal Enzymesmentioning

confidence: 99%

Section: Enzyme Expression and Purificationmentioning

confidence: 99%

Section: Strategy For Enzyme Screening On Realistic Lignocellulosic Smentioning

confidence: 99%

Section: Enzyme Mixture Optimizationmentioning

confidence: 99%

See 2 more Smart Citations

Strategy for Identification of Novel Fungal and Bacterial Glycosyl Hydrolase Hybrid Mixtures that can Efficiently Saccharify Pretreated Lignocellulosic Biomass

et al. 2010

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“…Significant progress has been made with fungal enzymes in identifying a minimum set of enzymes capable of degrading cellulose and biomass [49]. In the Trichoderma system, CBHI (GH7), CBHII, (GH6) and EG1 (GH6) are the three cellulases to produce >80% conversion of crystalline cellulose in the presence of b-glucosidase; all three contain CBM1 domains.…”

Section: Bioinformatic Approaches To Cellulase Discoverymentioning

confidence: 99%

Bacterial genomes: what they teach us about cellulose degradation

Brumm

2013

Biofuels

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Comparative Performance of Leading Pretreatment Technologies for Biological Conversion of Corn Stover, Poplar Wood, and Switchgrass to Sugars

Wyman

Dale

Balan

et al. 2013

Aqueous Pretreatment of Plant Biomass for Biological and Chemical Conversion to Fuels and Chemicals

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Mixture optimization of six core glycosyl hydrolases for maximizing saccharification of ammonia fiber expansion (AFEX) pretreated corn stover

Cited by 191 publications

References 31 publications

Strategy for Identification of Novel Fungal and Bacterial Glycosyl Hydrolase Hybrid Mixtures that can Efficiently Saccharify Pretreated Lignocellulosic Biomass

Strategy for Identification of Novel Fungal and Bacterial Glycosyl Hydrolase Hybrid Mixtures that can Efficiently Saccharify Pretreated Lignocellulosic Biomass

Bacterial genomes: what they teach us about cellulose degradation

Comparative Performance of Leading Pretreatment Technologies for Biological Conversion of Corn Stover, Poplar Wood, and Switchgrass to Sugars

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