Extraction of extracellular lipids from chemoautotrophic bacteria Serratia sp. ISTD04 for production of biodiesel

•Serratia sp. ISTD04 isolated from marble rock for CO2 sequestration.•Extraction of extracellular lipids from bacteria.•Transesterification indicated formation of biodiesel from lipids.•Saturated and unsaturated FAME was found to be 51% and 49% respectively. A CO2 sequestering bacterial strain, Serratia sp. ISTD04, that produces a significant amount of extracellular lipids was isolated from marble mine rocks. 14C labeling analysis revealed that the rate of assimilation of CO2 by the strain is 0.756×10−9μmolCO2fixedcell−1h−1. It was found to produce 466mg/l of extracellular lipid which was characterized using 1H NMR. After transesterification of lipids, the total saturated and unsaturated FAME was found to be 51% and 49% respectively. The major FAME contained in the biodiesel were palmitic acid methyl ester (C16:0), oleic acid methyl ester (C18:1) and 10-nonadecenoic acid methyl ester (C19:1). Biodiesel produced by Serratia sp. ISTD04 is balanced in terms of FAME composition of good quality. It also contained higher proportion of oleic acid (35%) which makes it suitable for utilization in existing engines. Thus, the strain can be harnessed commercially to sequester CO2 into biodiesel.