One-step production of biodiesel by wet Escherichia coli cells expressing a non-specific and methanol-resistant lipase

The efficient methanol-resistant biocatalysts with low costs are always desirable for biodiesel production. Here, an Escherichia coli whole-cell catalyst was constructed with the methanol-resistant MAS1 lipase being expressed intracellularly. Notably, this whole-cell catalyst showed significantly higher methanol-resistance than the purified MAS1 lipase. The whole-cell catalyst with the non-specific MAS1 lipase enabled efficient biodiesel production. Moreover, high-density fermentation was found to reduce the production costs and improve the catalytic activity of the whole-cell catalyst. The wet cells collected by centrifugation were directly used for fatty acid methyl ester (FAME) production from olive oil with one-step addition of methanol. Under the optimal conditions (catalyst loading of only 1.5 wt%, water content of 30 % (v/w), methanol content of 30 % (v/w) and reaction temperature of 29 °C), the maximum yield of 93.56 % was obtained. Furthermore, the whole-cell catalyst showed favorable reusability, with 85 % of the original activities left after a 4-cycle usage. Overall, the whole-cell catalyst reported in the present study would provide great potentials for the enzymatic production of biodiesels.