Applied metagenomics for biofuels development and environmental sustainability in biorefineries based on sugarcane

Abstract

During the bioethanol production process, different liquid and solid waste streams emerge, which hold the potential for its exploitation in a biorefinery process. Thus, waste streams can be treated by a simultaneous production of value added components additionally to bioethanol making the overall process more sustainable. In this scenario, anaerobic digestion of vinasse (the most abundant liquid waste in a biorefinery) arises as an interesting alternative, since in addition of promoting stabilization of organic matter, it also enables energy generation from biogas. Few studies have reported the potential to produce hydrogen and methane using sugarcane vinasse as a substrate. Most of them have covered a selection of the more appropriate type of reactor and operational conditions to the liquid waste in question, based on parameters of quality (organic matter conversion and values of production and yield of biogas), leaving a gap in relation to the studies of gas producing microbial communities. The application of metagenomic techniques can improve the overall performance of the anaerobic digestion in sugarcane-based biorefineries plants. In this plan is proposed the research internship at French National Institute for Agriculture Research (INRA) to assess the structural and functional dynamics of microbiomes in digesters producing hydrogen and methane from sugarcane vinasse, based on next-generation sequencing (NGS) using MiSeq Sequencing System (Illumina) technique. Highlighting the acidogenic biomass, 16S rDNA fingerprints, characterization of functional genes (hydA) and the development of probes for PCRq of homoacetogens will be performed. Still, techniques of how to regulate the homoacetogenic bacteria (HoA) will also be performed. Then, the best regulation condition will be applied in a hydrogen-producing system (CSTR) in order to obtain a balance between HPB and HoA, consequently, continuous hydrogen production. Such techniques focused on open cultures (non-sterile mixed cultures, microbiome) in anaerobic digesters will be used for the posterior application at CTBE/CNPEM after returning from the internship abroad. (AU)