Enhancement of bacterial cellulose production synergistic H2 and volatile fatty acids from fruit and vegetable waste through retting pretreatment
Li Zhao, Yixin Ma, Mukesh Kumar Awasthi, Dong Tian, Jinsong He, Mei Huang, Jianmei Zou, Yongjia Lei, Fei Shen
Abstract
Fruit and vegetable waste (FVW) is a sustainable substrate to obtain bacterial cellulose (BC). Here, retting pretreatment of FVW was conducted at 20°C for fixed durations (0, 7, 14, and 21 days) to release fermentable carbon sources and enhance BC production. At the same time, solid residues and BC culture effluent were anaerobic co-digestion to realize full utilization of FVW. Retting pretreatment of 14 d achieved the maximum BC yield of 4.09 g·L −1 and improved BC tensile strength by more than 2 times. Derivatives such as acetic acid, ethanol, and lactic acid promoted BC production, while propionic acid, butyric acid, valeric acid, and nitrite inhibited it. Besides, H 2 and volatile fatty acids were produced from anaerobic co-digestion, with yields of 78.81 mL·g −1 total solids and 8.52 g·L −1 , respectively, at a suitable solid residues to culture effluent ratio of 3:7. This study proposed a facile pretreatment method and integrated a multi-product process, offering a more applicable pathway for FVW valorization. • Fruit and vegetable waste (FVW) was employed for bacterial cellulose (BC) production. • Higher BC yield of 4.09 g·L −1 was achieved by retting pretreatment with 220 % increase. • Retting pretreatment solid residues and BC effluent were co-digested for H 2 and VFAs production. • A multi-product biorefinery process was integrated to yield BC, H 2 and VFAs from FVW.