Microbial Color Pigment Production from Waste Beer
Project no. 20061 · Status: Kapanmış · 2018
Summary
Waste utilization is a critical and important issue for the food industry related to the issues of environmental protection, pollution prevention and process economy. Utilization of waste and by-products for the production of high value-added products becomes compulsory due to economic and environmental issues since brewery industry generates large amounts of organic wastes. Although brewery waste is a negative cost factor for brewery industry, its rich content of complex carbohydrates, nitrogen and minerals opens avenues to the production of biotechnological products such as biofuel, enzymes, organic acids and bioactive compounds. In this study, red pigment by Monascus purpureus CMU001 in submerged fermentation system using waste beer/residual beer as an inexpensive substrate was produced. Alcohol and CO2 removed residual beer supplemented with 7.5 g/L of monosodium glutamate was used as the fermentation medium. Shaking speed and medium volume was found to affect red pigment synthesis by M.purpureus. Maximum red pigment production of 18.54 UA510nm was obtained with 200 rpm shaking speed, 50 ml of the fermentation medium, initial pH of 7.0, inoculation ratio of 2% (v/v). Several nitrogen sources (monosodium glutamate, malt sprouts, yeast extract, corn steep liquor, ammonium sulfate ((NH4)2SO4), peptone and urea) were investigated, and the highest pigment synthesis was obtained with monosodium glutamate. Promising results were obtained with corn steep liquor and yeast extract when used as the nitrogen source in pigment production. The optimum monosodium glutamate concentration was found to be 7.5 g/L. Kinetics of pigment and biomass formation was determined under the optimized fermentation conditions over a fermentation period of 8 days. Thermal and pH stability of red pigments produced by M.purpureus CMU 001 in submerged fermentation were also determined. The pigment stability was evaluated under different pH and temperature conditions. The thermal degradation of red pigments showed first-order kinetics while the temperature dependence of the degradation constants followed the Arrhenius model. The activation energies of red pigments were 15.68 and 10.45 kcal mol-1 at pH 4.0 and 6.0, respectively. The intensity of red pigment after autoclaving decayed by 70.19% and 27.47% at pH 4.0 and 6.0, respectively. According to these results, color degradation of the red pigment increased prominently with decreases in the pH and increases in the temperature values. This is the first article about the use of residual beer for pigment synthesis using M.purpureus in the submerged fermentation system.