Screening Of A Cellulase-producing Fungi Strain In Compost, Enzyme-producing Conditions And Application

Moisture is one of the most important processing parameters in aerobic composting of animal manure. Moisture influences the composting efficiency and the maturity of compost directly. Dehydration is very difficult for animal manure due to the dense network structure formed by substantive cellulose and hence affects composting process of animal manure.This study, is mainly focused on bio-dehydration of animal manure that contain substantive cellulose and high moisture content. The following studies were carried out:1.About 52 strains of bacteria, 28 strains of fungi and 15 strains of actinomyces were isolated from natural compost of cow manure by enrichment culture, culturing on cellulose-Congo red plate medium and fermenting in liquid medium. A potent cellulolytic fungi strain F12 was identified as Penicillium oxalicum based on the morphologic taxonomy and 18S rRNA gene sequence.2.The conditions of producing cellulase of Penicillium oxalicum F12 were investigated. The results showed that the optimum conditions were as follows: carbon source was bran and microcrystalline cellulose complex, nitrogen source was ammonium sulfate, initial pH value was 5~6, inoculation quantity was about 5%, culture temperature was 30~35℃, culture time was 120 h. On the conditions, the activities of CMCase and FPA were 47.5 IU·mL-1 and 11.1 IU·mL-1 respectively. Penicillium oxalicum F12 had the strongest decomposing ability to the cellulose materials, and its weight loss of filter paper and straw were 25.2% and 16% respectively.3.The dehydration of high humidity in the fermentation of straw powder in situ simulation test by inoculating Penicillium oxalicum F12 were performed. The results showed that dehydration of simulated compost reached 51.7g under inoculation of 5%, which accounted for 21.5% initial material moisture content. There were significant difference between the treatment and the control.4.The maximum of cellulase of Penicillium oxalicum F12 can be achieved in the temperature ranged from 30 to 35℃, initial pH from 4 to 8. Hence, Penicillium oxalicum F12 is suitable for the degradation of cellulose in initial stage of animal manure composting, and has applied potential in in situ bio-dehydration of compost.