Protein Enrichment of Brewery Spent Grains Using Aspergillus oryzae

Abstract

Solid state fermentation of brewery spent grain (BSG) was carried out in this study using Aspergillus oryzae. Fungi isolates obtained from the samples of brewery spent grain collected from Nigerian Brewery Plc., Ibadan, Oyo State, Nigeria, were isolated and identified. Isolate with high percentage of occurrence was tested for the ability to grow and improve protein content of spent grain. The isolate was used to carry out a solid state fermentation on the brewery spent grain to improve the percentage protein of the spent grain. Proximate analyses of the fermented samples were also carried out.

The fungus with the highest frequency of occurrence was identified as Aspergillus oryzae. The proximate analyses result revealed a significant increase in the percentage protein from 18.22% in the unfermented to 28.33% in the solid state fermented spent grain after 35 day of fermentation. The ash content of the spent grain also increased from 3.66 % to 7.4% in the fermented sample and a significant decrease in the carbohydrate from 22.05% to19.05% was observed, ether extract from 5.53% to 3.23%, and the fiber content also decreased from 18.11% to 13.99% in the brewery spent grain with increasing time.