title: Novel clostridial fusants in comparison with co-cultured counterpart species for enhanced production of biobutanol using green renewable and sustainable feedstock.
abstract: In this work, biobutanol was produced through simultaneous saccharification and fermentation (SSF) of wheat straw (WS) that traditionally produces acetone, butanol and ethanol solvents (ABE). Thermal stability was imparted to two mesophilic clostridial wild strains (Clostridium beijerinckii and Clostridium acetobutylicum) through protoplast fusion with that of a corresponding thermophilic clostridial species (Clostridium thermocellum). Production was pursued by the fused strains at 45 °C compared to that of the corresponding co-cultures at 35 °C. Results showed that the fused strains generally achieved higher production at 45 °C than that of the corresponding co-cultures at 35 °C. Highest butanol production of 13.82 g/L was recorded with C. beijerinckii fusant, with ABE solvents production of 23 g/L (yields of 0.17 and 0.57, respectively). Total sugar consumption of this strain was the highest among all strains and was 84%. Fused strains also showed immense level of tolerance towards butanol toxicity compared to the wild strains. Filter paper enzyme assay demonstrated that fused strains were able to produce cellulolytic enzymes in the range of 58.73-68.52 FPU/ml. Cellulosome producing C. thermocellum and its ability to ferment sugars offers a promising future in biofuels through eliminating the need to add external enzymes. Generally, productions reported in the present study were higher than literature where biobutanol stripping systems were employed to eliminate toxicity during production. This demonstrates a clear potential for improving productivity and yield at a larger-scale facility.
authors.affiliation: Department of Chemical Engineering, Ryerson University, Toronto, ON, M5B 2K3, Canada.
authors.forename: Kashif
authors.initials: K
authors.lastname: Syed
authors.affiliation: Department of Chemical Engineering, Ryerson University, Toronto, ON, M5B 2K3, Canada. ydahman@ryerson.ca.
authors.forename: Yaser
authors.initials: Y
authors.lastname: Dahman
mesh_terms: D000440:Butanols / Q000378:metabolism*; D046969:Clostridium acetobutylicum / Q000378:metabolism*; D046970:Clostridium beijerinckii / Q000378:metabolism*; D048013:Acetivibrio thermocellus / Q000378:metabolism*
chemical_list: D000440:Butanols
keywords: Biofuel; Biomass; Co-culture; Green; Protoplast fusion; Renewable energy; Simultaneous saccharification and fermentation; Wheat straw