Greener approach to the comprehensive utilization of algal biomass and oil using novel Clostridial fusants and bio-based solvents

Abstract

A greener method has been tested to utilize algal biomass as a feedstock to produce bio-oil in addition to acetone, butanol, and ethanol (ABE) products. Various hydrolysis treatments were used prior to fermentation including combination of thermal, chemical, and enzymatic, which resulted in maximum sugar release of 27.78 g/L. Bio-based terpenes was used instead of common toxic chemicals together with Clostridial fustants to produce bio-alcoholic fuels. Protoplast fusion technique were used to produce the novel Clostridia fusants (C. beijernickii + C. thermocellum and C. acetobutylicum + C. thermocellocum). Fused strains were then subjected to UV radiation for strain enhancement. Final fusansts showed clear improvement in thermal stability and resistance to biobutanol toxicity. Fermentation experiments showed maximum biobutanol final production of 7.98 g/L using CbCt versus 7.39 g/L using CaCt. Oil extraction from virgin algae was tested using a green, bio-based approach using terpenes with ultrasonication and green Bligh and Dyer method, separately. In preliminary study on algal biomass, the combinations of ultrasonication followed by the green Bligh and Dyer have resulted in oil yield of 46.27% (d-limonene) and 39.85% (p-cymene). Oil extraction from an algae sample following fermentation using the combined extraction method resulted in significantly higher oil yield of 65.04%.