Isolation and identification of anaerobic bacteria from coconut wastewater factory for ethanol, butanol and 2, 3 butanediol production

•Screening and identification of novel anaerobic bacteria from agricultural industrial sources that can be applied in biofuels bioprocess combined with wastewater treatment.•Other gainful solvents for instance acetone, butanol and ethanol which can be produced from fermentation are investigated in compare to a well-known solventogenic Clostridium spp.•Coconut factory wastewater is determined for a potential to be renewable carbon sources for ABE fermentation.

Wastewater from coconut processing industry contains carbohydrates which are potential substrates for butanol and ethanol fermentation process. In this research, five isolates of anaerobic bacteria were screened from coconut wastewater. To identify the species and solvent production, the morphological characterization, 16S rRNA gene identification and biochemical test were performed. It was discovered that the isolate COCON2 belongs to the species Pectinatus frisingensis with 16S rRNA gene sequence identity of 98%, whereas COCON4, COCON9 and COCON11 are closely related to Pectinatus portalensis (with 16S rRNA sequence identity percentage of 98, 99 and 99% respectively). As for COCON6, it is similar to Klebsiella oxytoca with 98% 16S rRNA sequence similarity. The solvent production of Pectinatus spp. under anaerobic condition from 20 g/L mannose in 30 mL synthetic medium showed acetate as the main product (1.877-2.146 g/L). In conclusion, naturally selected bacteria have the ability to convert sugar into acetate and ethanol which are metabolites from cellular respiration in optimum condition.