Biodiesel synthesis from non-edible oil using agro-waste and evaluation of its physicochemical properties

Change in the climatic conditions due to uncontrolled emission of carbon dioxide is continuously encouraging to search alternative renewable energy sources. Corn stover is one of the several feedstocks being considered as growth medium for oil producing bacteria. India ranks third in the production of corn in the world. The present study focused on biodiesel synthesis from microbial oil, chemical profiling and evaluation of physicochemical properties of produced biodiesel. The bacterium was isolated from food waste resources and identified as Bacillus amyloliquefaciens (MF510169) on the basis of morphological‚ biochemical characters and 16S rRNA sequencing. The bacterium B. amyloliquefaciens (MF510169) was grown on corn stover as an ideal agro-waste feedstock. The bacterium grown on corn stover peels revealed maximum lipid production after acid hydrolysis (0.25% HCl) over other feedstocks used under study. The bacterium produces 3.8% oil under operating parameters, i.e. inoculum size, density, carbon and nitrogen source, C/N ratio, temperature, pH, rotational speed and fermentation period. The oil was transesterified using sulphuric acid (0.12%) as a catalyst to form fatty acids methyl esters. Transesterification reaction was optimised at various parameters like catalyst type, catalyst loading, oil: methanol ratio, temperature and reaction time. The chemical profiling of FAMEs revealed hexadecanoic acid methyl ester, 9-1, 2 octadecanoic acid methyl ester, octadecanoic acid methyl ester and methyl stearate as characterised by using GC–MS, GC-FID, FTIR and NMR techniques. The physicochemical properties of transesterified biodiesel revealed 85% similarity with the ASTM International Standards. The produced biodiesel from Bacillus could be exploited at commercial level after successful engine trial tests.