Европейский журнал экспериментальной биологии Открытый доступ

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Formulation of microbial growth media using brewers’ spent grains (BSG)and growth rate assessment with three bacterial species

Archibong Etim J., Obuboegbunam Eberechukwu C., Ewelukwa Uju C., Onuora Veronica C., Ezemba Constance C., Okeke Chidi B. and Okafor Ugochukwu C

Studies on the formulation of microbial growth media from brewers’ spent grains and their gelling properties were carried out. Three bacterial species; Staphylococcus aureus, Streptococcus pyogenes and Escherichia coli were used to assess the ability of the formulated media to support microbial growth. Two formulations of brewers’ spent grains obtained from 100% barley mash and a mixture of 80% barley and 20% sorghum mash were used. Proximate analysis of the dried spent grains from lautered 100% barley mash gave protein, fat, ash, moisture, fibre and carbohydrate content as 21.26%, 7.8%, 2.8%, 7.89%, 13.7% and 45.59% respectively. Whereas, analysis of the mixed dried spent grains gave 19.26%, 4.6%, 1.4%, 6.25%, 15.52% and 50.77% for protein, fat, ash, moisture, fibre and carbohydrate respectively. Total plate counts of test microorganisms on formulated media were compared to that of their standard growth media. At P ≤ 0.05, the result showed a significant difference of total bacterial count between organisms grown on formulated media and those grown on standard media. In the formulations at different ratios with gelling agent, efficient gelling properties were obtained with active growth of tested microorganisms. Thus, brewers’ spent grains can be harnessed into microbial growth media for cost reduction.