Morphologically favorable mutant of Trichoderma reesei for low viscosity cellulase production

Abstract

Metabolite production by filamentous fungi hampered because of high viscosity generated during growth. Low viscosity fermentation by mold is one of the preferred ways of large scale enzymes production. Cellulolytic enzymes play a key role during the process of lignocellulosic biomass conversion. In this study, a mutant RC‐23‐1 was isolated through mutagenesis (diethyl sulfate followed by UV) of Trichoderma reesei RUT‐C30. RCRC‐23‐1 not only gave higher cellulase production but also generated lower viscosity during enzyme production. Viscosity of mutant growth was more than three times lower than parent strain. RC‐23‐1 shows unique, yeast‐like colony morphology on solid media and small pellet‐like growth in liquid media. This mutant did not spread like mold on solid media. This mutant produces cellulases constitutively when grown in sugars. Using only glucose, the cellulase production was 4.1 FPU/ml. Among polysaccharides (avicel, xylan, and pectin), avicel gave maximum of 6.2 FPU/ml and pretreated biomass (rice straw, wheat straw and sugarcane bagasse) produced 5.1–5.8 FPU/ml. At 7 L scale reactor, fed‐batch process was designed for cellulase production using different carbon and nitrogen sources. Maximum yield of cellulases was 182 FPU/g of lactose consumed was observed in fed‐batch process. The produced enzyme used for hydrolysis of acid pretreated rice straw (20% solid loading) and maximum of 60% glucan conversion was observed. RC‐23‐1 mutant is good candidate for large scale cellulase production and could be a model strain to study mold to yeast‐like transformation.

A Combined Study on Optimization, In Silico Modeling, and Genetic Modification of Large Scale Microbial Cellulase Production

“…T. reesei was randomly altered at Rutgers University, resulting in the strain RUT-C30, which demonstrated a 20-fold increase in cellulase secretion. According to Adsul et al, [ 83 ], mutant T. reesei RUT-C30 is one of the most widely used fungal strains for commercial cellulase production. Bacillus pumilus was randomly altered, resulting in cellulase yields four times greater than the wild-type strain [ 84 ].…”

The Role of Microorganisms in the Isolation of Nanocellulose from Plant Biomass

“…Bacteria such as Gluconacetobacter xylinus are well known in nanocellulose production. This bacterium produces cellulose in its extracellular matrix, which can be harvested and further processed into nanocellulose [12], while several fungi such as Trichoderma reesei are used to produce cellulase enzymes that can break down cellulose into its component parts, including nanocellulose [13]. Microbial enzymes are used in a process called enzymatic hydrolysis, which involves treating the plant material with the enzyme solution to break down the cellulose into nanocellulose [14].…”