Integrated biorefinery development using winery waste streams for the production of bacterial cellulose, succinic acid and value-added fractions.

ABSTRACT

An integrated biorefinery has been developed using winery wastes (grape pomace-GP, stalks-GS, wine lees-WL). Bacterial cellulose was produced from GP extracted free sugars. Grape-seed oil and polyphenols were extracted from GP. Experimental design was employed to optimize lignin removal (50.8%) from mixtures of remaining GP solids and GS via NaOH (1.19% w/v) treatment at 70°C for 30 min. Delignification liquid contained condensed tannins with 76% Stiasny number. Enzymatic hydrolysis produced a sugar-rich hydrolysate (40.2 g/L sugars). Ethanol, antioxidants, tartaric acid and nutrient-rich hydrolysate were produced from WL. The crude hydrolysates were used in fed-batch Actinobacillus succinogenes cultures for 37.2 g/L succinic acid production. The biorefinery produces 42.65 g bacterial cellulose, 24.3 g oil, 40.3 g phenolic-rich extract with 1.41 Antioxidant Activity Index, 80.2 g ethanol, 624.8 g crude tannin extract, 20.03 g tartaric acid and 157.8 g succinic acid from 1 kg of each waste stream.