Chlamydomonas reinhardtii and Microbacterium forte sp. nov.,a mutualistic association that favor sustainable hydrogen production

Abstract

AbstractA multispecies bacterial community includingMicrobacterium fortesp. nov.,Stenotrophomonas goyisp. nov., andBacillus cereusgreatly promoted sustained hydrogen production by the microalgaChlamydomonas reinhardtiiwhen cocultivated in mannitol- and yeast extract-containing medium (up to 313 mL·L-1). Alga viability was also largely prolonged in the cocultures (>45 days) without any nutrient supplementation. Among the bacterial community,Microbacterium fortesp. nov. was the main responsible for the hydrogen production improvement. Nonetheless, the use of the entire bacterial community allowed a better growth of the alga during hydrogen production.Chlamydomonas reinhardtiiandMicrobacterium fortesp. nov. established a mutualistic association, based on the release of ammonium and acetic acid from the bacterium, while the alga provided sulfur-containing metabolites and complemented the bacterial auxotrophy for biotin and thiamine. This study uncovers the potential of the Chlamydomonas-bacteria consortia for durable and stable H2production while allowing the simultaneous production of biomass.