RESUMEN
Cellulase, xylanase, and ß-glucosidase production was studied on novel nano-shear pretreated corn stover by the mixed fungi culture. The high shear force from a modified Tayor-Couette nano-shear mixing reactor efficiently disintegrated corn stover, resulting in a homogeneous watery mash with particles in much reduced size. Scanning electron microscope study showed visible mini-pores on the fiber cell wall surface, which could improve the accessibility of the pretreated corn stover to microorganisms. Mixed fungal culture of Trichoderma reesei RUT-C30 and Aspergillus niger produced enzymes with higher cellulolytic and xylanolytic activities on corn stover pretreated with nano-shear mixing reactor, in comparison with other pretreatment methods, including acid and ammonia fiber explosion (AFEX) pretreatment. The hydrolytic potential of the whole fermentation broth from the mixed fungi was studied, and the possibility of applying the whole cell saccharification concept was also investigated to further reduce the cost of lignocellulose hydrolysis.
Asunto(s)
Aspergillus niger/metabolismo , Celulasa/metabolismo , Lignina/metabolismo , Trichoderma/metabolismo , Xilosidasas/metabolismo , beta-Glucosidasa/metabolismo , Aspergillus niger/crecimiento & desarrollo , Biomasa , Celulasa/aislamiento & purificación , Hidrólisis , Fenómenos Físicos , Trichoderma/crecimiento & desarrollo , Xilosidasas/aislamiento & purificación , Zea mays/metabolismo , beta-Glucosidasa/aislamiento & purificaciónRESUMEN
The use of immobilized enzymes during saccharification of lignocelluloses enables the continuous process of enzymatic hydrolysis and repeatable use of enzyme, resulting in reduced operational cost. Novel nano-biocarriers were developed by layer-by-layer deposition of carbon nanotube (CNT) on the foam structures, and their efficiency for enzyme immobilization was demonstrated with cellulase and ß-glucosidase. A three-fold enhancement was achieved in the activity of cellulase immobilized on CNT coated polyurethane foam. In addition, both cellulase and ß-glucosidase immobilized on the CNT-foam showed much better storage stability and operational stability than the ones immobilized on the commercial biocarrier (Celite), which is critical for a continuous operation. CNT coated monolith was also developed as a biocarrier, offering high surface area and geometric stability. These nano-biocarriers are promising candidates for the efficient saccharification of biomass and to reduce carbon footprint and cost of the equipment.