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Reducing β-glucosidase supplementation during cellulase recovery using engineered strain for successive lignocellulose bioconversion

Guo, Hong, Zou, Shaolan, Liu, Boshi, Su, Rongxin, Huang, Renliang, Qi, Wei, Zhang, Minhua, He, Zhimin
Bioresource technology 2015 v.187 pp. 362-368
beta-glucosidase, biotransformation, cellulose, corn cobs, endo-1,4-beta-glucanase, ethanol, fermentation, genetically engineered microorganisms, lignocellulose
Enzyme recycling by re-adsorption is one of the primary methods for reducing enzyme usage in lignocellulose conversion. This work proposes the combination of an engineered yeast strain that expresses β-glucosidase with enzyme recycling to reduce the amount of supplemented β-glucosidase in enzyme recycling experiments. Using the engineered strain, a slight increase in ethanol concentration was obtained after a 96-h fermentation of pretreated corncobs. Ethanol concentrations increased by 34.7% and 62.7% in the following two recycle rounds using the engineered strain compared with those using its parental strain without β-glucosidase addition. Furthermore, with the addition of β-glucosidase at 30CBU/g cellulose, the ethanol concentration after two recycle rounds exceeded 90% of that observed in the first SSF round with the engineered strain at a high initial cellulase loading of 45FPU/g cellulose.