Caproate production from xylose by mesophilic mixed culture fermentation. (July 2020)

• Record Type: Journal Article
• Authors: Qian, Ding-Kang; Geng, Zi-Qian; Sun, Ting; Dai, Kun; Zhang, Wei; Jianxiong Zeng, Raymond; Zhang, Fang
• Is Part Of: Bioresource technology. Volume 308(2020)
• Publication Date: 2020-07
• Subjects: Xylose -- Caproate -- Mixed culture fermentation -- Caproiciproducens -- The fatty acid biosynthesis pathway; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2020.123318
• Languages: English
• ISSNs: 0960-8524

Abstract

Graphical abstract: Highlights: Converting xylose to caproate (C6) by mixed culture fermentation was verified. The maximum concentration of caproate was 2.06 g/L in a batch reactor. Caproate concentration were between 0.45 and 1.07 g/L at pH 5.0 in a CSTR reactor. Genus Caproiciproducens was unexpectedly identified as the main caproate producer. Fatty acid biosynthesis, not reverse β-oxidation, may be the pathway to produce C6. Abstract: Caproate production by mixed culture fermentation (MCF) is economically attractive. Xylose is known as the second most abundant sugar in nature, however, producing caproate from xylose is never reported. In this study, caproate production from xylose by mesophilic MCF was firstly investigated. The results showed that as pH decreasing to 5.0, the caproate concentration was 2.06 g/L in a batch reactor and was between 0.45 and 1.07 g/L in a continuously stirred reactor. Microbial analysis illustrated that Caproiciproducens and Clostridium_sensu_stricto_12, as two main identified caproate producers, occupied over 50% and around 10% of mixed culture, respectively. Thus, caproate production from xylose was proposed via the fatty acid biosynthesis pathway, not the well-known reverse β-oxidation pathway. These unexpected differences from literatures gains more understanding about caproate production from organic substrates via MCF.