Efficient conversion of corn straw to feed protein through solid-state fermentation using a thermophilic microbial consortium

Abstract

Solid-state fermentation of lignocellulosic waste to produce feed protein is a means of realising solid waste. However, low efficiency and susceptibility to microbial contamination remain significant challenges in feed protein production through room-temperature solid-state fermentation. In this study, thermophilic microbiomes were enriched. After adaptive and nitrogen acclimation, microbiomes with the combined functions of ‘thermophilic-rapid decomposition-nitrogen conversion’ were obtained and used for feed protein production. High-throughput sequencing and Kyoto Encyclopedia of Genes and Genomes metabolic pathway prediction techniques were used to assess the mechanisms underlying microbial involvement in substance conversion. The results showed that the microbiomes decomposed 78.21 %–81.73 % of straw within 7 days. After nitrogen acclimation, the nitrogen utilisation rate and the true protein content of the microbiomes improved by 19.22 %–26.96 % and 56.14 %–71.99 %, respectively. Fed-batch enzymatic saccharification and fermentation reduced the fermentation time by 28.5 %. Domesticated microbiomes increased the abundance of bacteria and fungi in the fermentation system, enhancing carbon metabolism and the urea cycle. This study presents a novel approach for the high-value utilisation of lignocellulose waste.