Production of cellulases and β-glucosidase in Trichoderma reesei mutated by proton beam irradiation

Improved Cordycepin Production by Cordyceps militaris KYL05 Using Casein Hydrolysate in Submerged Conditions

Cordycepin, a beneficial bioactive product specifically found in Cordyceps, has received attention in various bioindustrial applications such as in pharmaceuticals, functional foods, and cosmetics, due to its significant functions. However, low productivity of cordycepin is a barrier to commercialization. In this study, Cordyceps militaris was mutated by UV irradiation to improve the cordycepin production. The highest producer KYL05 strain was finally selected and its cordycepin production was increased about 1.5-fold compared to wild type. In addition, the effects of culture conditions were fundamentally investigated. Optimal conditions were as follows: pH 6, temperature of 25 °C, shaking speed of 150 rpm, and culture time of 6 days. Effects of medium component on cordycepin production were also investigated by using various carbon and nitrogen sources. It was found that glucose and casein hydrolysate (CH) were most effective as carbon and nitrogen sources in cordycepin production (2.3-fold improvement) with maximum cordycepin production of about 445 mg/L. In particular, production was significantly affected by CH. These results should be of value in improving the efficiency of mass production of cordycepin.

Solid state bioconversion of lignocellulosic residues by Inonotus obliquus for production of cellulolytic enzymes and saccharification

White rot fungi have been usually considered for lignin degradation and ligninolytic enzyme production. To understand whether the white rot fungus Inonotus obliquus was able to produce highly efficient cellulase system, the production of cellulolytic enzyme cocktails was optimized under solid state fermentation. The activities of CMCase, FPase, and β-glucosidase reached their maximum of 27.15IU/g, 3.16IU/g and 2.53IU/g using wheat bran at 40% (v/w) inoculum level, initial pH of 6.0 and substrate-moisture ratio of 1:2.5, respectively. The enzyme cocktail exhibited promising properties in terms of high catalytic activity at 40-60°C and at pH 3.0-4.5, indicating that the cellulolytic enzymes represent thermophilic and acidophilic characteristics. Saccharification of raw wheat straw and rice straw by the cellulolytic enzyme cocktail sampled on Day 12 resulted in the release of reducing sugar of 130.24mg/g and 125.36mg/g of substrate after 48h of hydrolysis, respectively.