Optimization of temperature in Aspergillus niger (USM F4) assisted solid state fermentation for protein enrichment of wheat bran

A study was conducted to identify the optimal temperature and fermentation duration for enhancing the crude protein (CP) content of wheat bran through solid-state fermentation (SSF) induced by Aspergillus niger USM F4. The wheat bran underwent microbial fermentation in solid state at three temperature levels: 25, 35 and 45°C, over a period of 14 days. At 2-day intervals, the fermentation process was halted, and duplicate samples were collected from each temperature setting. These samples were subsequently dried in an oven at 60°C for 24 hours and analyzed for crude protein content. The findings revealed a significant (P<0.05) increase in CP content for all fermented samples compared to the unfermented sample. The highest crude protein values were observed at 25°C on day 10 (46.75%), at 35°C on day 14 (53.95%), and at 45°C on day 14 (59.09%). These values represented increments of 222.38%, 272.06%, and 307.50%, respectively, compared to the initial protein content of 7.73% recorded on day 0. The study results identified the optimum temperature for maximum crude protein production in wheat bran fermented by Aspergillus niger USM F4 under solid-state fermentation as 45°C for a 14-day incubation period. Additionally, it suggests that fermented wheat bran could serve as a cost-effective and protein-enriched feed resource in the livestock industry.