Design and application of an efficient cellulose-degrading microbial consortium and carboxymethyl cellulase production optimization

Abstract

Microbial consortia with high cellulase activities can speed up the composting of agricultural wastes with high cellulose contents and promote the beneficial utilization of agricultural wastes. In this paper, rabbit feces and sesame oil cake were used as feedstocks for compost production. Cellulose-degrading microbial strains were isolated from compost samples taken at the different composting stages and screened via Congo red staining and filter paper degradation test. Seven strains, Trichoderma reesei, Escherichia fergusonii, Proteus vulgaris, Aspergillus glaucus, Bacillus mycoides, Corynebacterium glutamicum, and Serratia marcescens, with high activities of carboxymethyl cellulase (CMCase), filter paper cellulase (FPase), and β-glucosidase (β-Gase) were identified and selected for consortium design. Six microbial consortia were designed with these strains. Compared with the other five consortia, consortium VI composed of all seven strains displayed the highest cellulase activities, 141.89, 104.56, and 131.18 U/ml of CMCase, FPase, and β-Gase, respectively. The single factor approach and response surface method were employed to optimize CMCase production of consortium VI. The optimized conditions were: culture time 4.25 days, culture temperature 35.5°C, pH 6.6, and inoculum volume 5% (v/v). Under these optimized conditions, the CMCase activity of consortium VI was up to 170.83 U/ml. Fermentation experiment of rabbit feces was carried out by using the consortium VI cultured under the optimal conditions. It was found that the application effect was better than other treatments, and the fermentation efficiency and nutrient content of the pile were significantly improved. This study provides a basis for the design of microbial consortia for the composting of agricultural wastes with high cellulose contents and provides a support for beneficial utilization of agricultural wastes.

Screening of cellulose-degrading yeast and evaluation of its potential for degradation of coconut oil cake

“…In rural areas of China, the solid waste represented by COC is difficult to treat. The complex composition and the presence of rich polysaccharide fibers such as cellulose, which are difficult to degrade, lead to waste accumulation and environmental pollution ( Zhang and Dong, 2022 ).…”

Degradation of Triazole Fungicides by Plant Growth-Promoting Bacteria from Contaminated Agricultural Soil

“…Their ability to convert atmospheric nitrogen into ammonia [ 26 , 30 , 31 ], as well as insoluble inorganic phosphate compounds into available forms [ 26 , 55 , 56 ], plays a vital role in providing essential nutrients that living organisms can use for biosynthesis. Additionally, during the growth of our strains, cellulose degradation was also observed, facilitating the conversion of organic waste into valuable organic matter and contributing to the reduction of the C:N ratio while also enhancing soil productivity [ 57 , 58 ]. The ability of the three isolates to produce IAA, a crucial growth-augmenting phytohormone, becomes especially significant for survival in harsh environments.…”

Screening of cellulose-degrading bacteria and optimization of cellulase production from Bacillus cereus A49 through response surface methodology

“…In another study, an F3 strain belonging to Bacillus amyloliquefaciens, isolated from fermented soybean products, displayed a cellulase activity of 21.14 U/mL under optimal cultivation conditions (37 °C, pH 7.0, and 6% inoculum volume) 35 . Likewise, the CMCase activity of Bacillus subtilis N5 identified from cow manure compost reached 189.27 U/mL under the most favorable culture conditions (pH 5.0, and 40 °C) 36 . Similarly, in this study, the culture conditions of the isolates were optimized through changes in agitation speed, cultivation temperature, medium concentration and inoculation volume.…”