In the quest for inexpensive feedstocks for the cost-effective production of liquid fuels, we
have examined gaseous substrates that could be made available at low cost and sufficiently
large scale for industrial fuel production. Here, attempt is made at simulating a new
bioconversion scheme that effectively converts syngas, generated from gasification of natural
gas into lipids that can be used for biodiesel production. An integrated conversion method
comprising a two-stage system. In the first stage, an anaerobic bioreactor converts mixtures
of gases of CO2 and CO or H2 to acetic acid, using the anaerobic acetogen Moorella
thermoacetica. The acetic acid product is fed as a substrate to a second bioreactor, where it is
converted aerobically into lipids by an engineered oleaginous yeast, Yarrowia lipolytica. The
integrated continuous bench-scale reactor system produced 36% yield of C16-C18
triacylglycerides directly from synthesis gas, with an overall productivity of 34.48% and
carbon conversion efficiency of 18.60%. The novel Bio-GTL synthesis route developed is
ascertained to be technically viable with great potential of competing favourably with the
conventional Fischer – Tropsch process route if further research on improving the process
such as; engineering micro-organisms with wider specificity and so on are carried out.