Hydrogen production from vegetable waste by bioaugmentation of indigenous fermentative communities

This work adopted an innovative approach for fermentative H₂ production from common domestic organic waste, at 28 °C, in the absence of pretreatment: the self-fermentation of non-sterile vegetable waste and the bioaugmentation of microbial indigenous fermenting communities. For this purpose, three new H₂-producing strains, Buttiauxella sp. 4, Rahnella sp. 10 and Raoultella sp. 47, isolated and enriched from vegetable waste, were individually tested on two types of vegetable waste and compared with a bacterial artificial consortium composed of the three strains put together. The three single strains were also characterized for their ability to produce H ₂ on different sugars, such as xylose, arabinose and cellobiose, as these are key products of hydrolysis of cellulose and hemicelluloses. H ₂ production occurred from self-fermentation with yields ranging from 18.08 to 21.95 ml H₂/g VS. All bacterial inocula promoted a significant increase of the H₂ yield and the H₂ production rate, compared to the self-fermentation. The inocula of the artificial consortium yielded the maximum H₂ production of 85.65 ml H ₂/g VS with the highest H₂ production rate of 2.56 ml H₂/h.