Refining of wine lees and cheese whey for the production of microbial oil, polyphenol‐rich extracts and value‐added co‐products

Abstract BACKGROUND Refining of renewable resources for the production of various end‐products should be applied in order to develop sustainable processes and ensure the transition to the bio‐economy era. With this principle in mind, a novel integrated biorefinery has been developed based on cheese whey and wine lees valorization. RESULTS Polyphenols, tartrate salts and ethanol were extracted from wine lees, while the remaining solids enriched in yeast cells were converted into nutrient‐rich fermentation supplements. The composition of phenolics varied between solid and liquid fractions of wine lees. Protein concentrate was separated from cheese whey via ultrafiltration, while the concentrated lactose‐rich permeate stream was supplemented with wine lees derived hydrolysates to form fermentation media for microbial oil production by Cryptococcus curvatus and Mortierella ramanniana . Functional oil containing 4.5% (w/w) of the omega‐6 fatty acid γ‐linolenic acid was produced in shake flask cultures by Mortierella ramanniana with total dry weight of 25.8 g L −1 and 30.6% (w/w) lipid content. Fed‐batch bioreactor cultures with Cryptococcus curvatus using only crude resources led to one of the highest lipid concentrations (33.1 g L −1 ) reported in literature‐cited publications using cheese whey. CONCLUSION This is the first study proposing the integrated refining of cheese whey and wine lees for the production of both commodity and speciality products, namely whey protein concentrate, antioxidants, ethanol, tartrate salts and microbial oil. © 2017 Society of Chemical Industry