Optimization Studies for Selective Recovery of Phenolics from Wine Wastes

The objective of the present study was the recovery and selective separation of phenolics from grape marc and lees, two primary wastes from wine-making industry, with solvent extraction method, optimized using One-Factor-at-a-Time method (OFAT) and Response Surface Methodology (RSM). Phenolics from the whole fresh grapes have been studied in previous work, but not the valorization of wine wastes and their phenolic content. Extraction resulted in 19, 15 and 10 mg/g (dry weight) total phenolics with 96%, 87% and 64% antioxidant activity from red, white marc and white lees, respectively. Extracts thus obtained were subsequently treated with several sorbents followed by HCl-desorption. NaOH and CH3OH treated zeolite and aluminum oxide, respectively, performed better, separating phenolics up to 93% from total sugars. The latter resulted in a fraction containing up to 50% of the initial phenolics holding the antioxidant activity (up to 85%) of the initial extract. The results indicate the significance of the applied methodology being fast and low cost for the selective recovery of phenolics from wine wastes.

Clean Monascus pigments production from Chinese rice wine wastes through submerged fermentation

The potential for Monascus pigments(MPs)production in a mixture of Chinese rice wine lees,soaked rice wastewater and broken rice was explored.MPs production reached 120.1 U/mL with optimal solid-liquid ratio of culture medium 1:10 and 20 g/L broken rice addition at shake flask level.We further explored the effects of stirring speed on MPs production in 7.5 L agitated bioreactor.The stirring speed had a great impact on cell morphology and the maximum MPs concentration and yield were 128.4 U/mL and 8174 U/g respectively at 400 rpm.The soluble chemical oxygen demand for the soaked rice wastewater decreased by 78.7%,which was mainly due to the intake of carbohydrates,organic acids and amino acids.Furthermore,a simultaneous fermentation process and production system with two-stage stirring speed control strategy was further developed in the 50 L pilot scale,in which the MPs production reached 158.9 U/mL.Meanwhile,Chinese rice wine wastes were fully utilized without addition of organic solvents during the process and no generation of new waste.Our results showed that Monascus was capable of converting Chinese rice wine wastes into natural pigments by submerged fermentation,which could provide an economic and environmentally friendly approach to reduce the cost of wastes treatment as well as high-value utilization.