Production of ethanol by marine bacterium M1 using domestic waste

Abstract

Marine micro-organisms are attaining great significance in the field of biotechnology. The present study focuses on isolation of ethanol-producing bacteria from marine samples. Total ten ethanol-tolerant strains were isolated. Use of wastes in generating energy is now in prime focus. In this study, different domestic wastes (paper, kitchen, garden, and fruit pulp) were used as the low cost substrate for ethanol fermentation. The bacterial strain E4 in the kitchen waste and the fruit pulp waste provided the best outcome for ethanol production via colorimetric assay. The ethanol estimation through High Performance Liquid Chromatograpy (HPLC) showed the presence of relevant peak of ethanol in the fermentation broth. Further the ethanol production was confirmed using Gass chromatography- Mass Spectrometery (GC-MS). The stain was characterized and identified as member of Firmicutes by 16SrRNA gene sequencing based molecular approach. High ethanol productivity (21 g l−1 h−1) was obtained after distillation when the marine strain M1 was used in a continuous ethanol fermentation process. Ethanol production was further optimized through Response surface method. RSM based process optimization revealed a 25-fold increase in ethanol production using 4%w/w fruit pulp waste at 30ºC at 160 rpm. In the present study the marine strain is reported first time for ethanol production using domestic wastes as cheap substrate.