Combined fungal and bacterial pretreatment of wheat and pearl millet straw for biogas production - A study from batch to continuous stirred tank reactors

In present study, chitinolytic bacteria were employed to bioaugment the biogas production from fungal pretreated agricultural residues. The fungal pretreatment of wheat and pearl millet straw was done by Chaetomium globosporum. Pretreated straw were digested anaerobically at batch scale with and without the presence of chitinolytic bacteria. Contrary to untreated samples, the addition of chitionolytic bacteria with pretreated wheat and pearl millet straw provided 41 and 57% higher biogas yield. The study was further upscaled to continuous stirred tank reactors. At continuous scale too, wheat straw pretreated with Chaetomium globosporum combined with chitinolytic bacteria resulted in 16% higher biogas yield in contrast to untreated straw. Higher abundance of methanogens was detected in reactors running with pretreated wheat straw during microbial community analysis. The identified bacteria belonged mostly to Firmicutes, Bacteroidetes, Proteobacteria phyla.

Automated summary

In this study, chitinolytic bacteria were used for bioaugmentation of fungal pretreated agricultural residues to enhance biogas production. Batch and continuous experiments showed that the addition of chitinolytic bacteria to wheat and pearl millet straw pretreated with Chaetomium globosporum resulted in increased biogas yield. Microbial community analysis revealed higher abundance of methanogens in reactors running with pretreated wheat straw, mainly consisting of Firmicutes, Bacteroidetes, Proteobacteria phyla.