Inoculum pretreatment differentially affects the active microbial community performing mesophilic and thermophilic dark fermentation of xylose. (10th May 2018)

• Record Type: Journal Article
• Authors: Dessì, Paolo; Porca, Estefania; Frunzo, Luigi; Lakaniemi, Aino–Maija; Collins, Gavin; Esposito, Giovanni; Lens, Piet N.L.
• Is Part Of: International journal of hydrogen energy. Volume 43:Number 19(2018)
• Page Start: 9233
• Page End: 9245
• Publication Date: 2018-05-10
• Subjects: Biohydrogen -- pH shock -- Temperature shock -- Clostridium -- Lactobacillus -- MiSeq; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2018.03.117
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: The influence of different inoculum pretreatments (pH and temperature shocks) on mesophilic (37 °C) and thermophilic (55 °C) dark fermentative H2 production from xylose (50 mM) and, for the first time, on the composition of the active microbial community was evaluated. At 37 °C, an acidic shock (pH 3, 24 h) resulted in the highest yield of 0.8 mol H2 mol −1 xylose. The H2 and butyrate yield correlated with the relative abundance of Clostridiaceae in the mesophilic active microbial community, whereas Lactobacillaceae were the most abundant non-hydrogenic competitors according to RNA-based analysis. At 55 °C, Clostridium and Thermoanaerobacterium were linked to H2 production, but only an alkaline shock (pH 10, 24 h) repressed lactate production, resulting in the highest yield of 1.2 mol H2 mol −1 xylose. This study showed that pretreatments differentially affect the structure and productivity of the active mesophilic and thermophilic microbial community developed from an inoculum. Graphical abstract: Highlights: Temperature and pH shock differentially affected dark fermentation of xylose. The effect of pretreatments on the community was studied using a RNA-based approach. Acidic or alkaline shocks led to the highest H2 yield at 37 and 55 °C, respectively. At 37 °C, relative abundance of Clostridiaceae and H2 yield correlated linearly. At 55 °C, lactate production was repressed only by an alkaline shock pretreatment.