Selection of white-rot basidiomycetes for bioconversion of mustard (Brassica compestris) straw under solid-state fermentation into energy substrate for rumen micro-organism.

AIMS

Selection of white-rot fungi of bio-conversion of mustard straw (MS) into feed for ruminants.

METHODS AND RESULTS

Mustard straw was cultured with Ganoderma applanatum, Coriolus versicolor and Phanerochaete chrysosporium for solid-state fermentation at 35 degrees C from 7 to 63 days for delignification and for 21 days to study dry matter digestibility and protein enrichment. Lignin loss in fungus cultured straw varied between 100 and 470 g kg(-1) lignin. Delignification was higher between 7 and 28 days fermentation with C. versicolor. Among the three fungi P. chrysosporium was the most effective in degrading lignin for longer fermentation. In-vitro dry matter digestibility (IVDMD) and crude protein content was higher in C. versicolor cultured straw. Large quantity of straw was cultured by C. versicolor for 21 days, for in vivo evaluation. Mean pH and metabolites of rumen fermentation were not different while, pH and volatile fatty acid increased at 6 h postfermentation on cultured straw feeding. Cultured straw fermentation increased (P = 0.001) small holotricks and reduced (P = 0.005) large holotricks population. Fungus cultures straw did not improve microbial enzyme concentration.

CONCLUSIONS

Coriolus versicolor and P. chrysosporium were the promising fungus for MS bio-delignification.

SIGNIFICANCE AND IMPACT OF THE STUDY

Coriolus versicolor treated MS improved dry matter digestibility and protein content.