New fungal lipases for biodiesel production

Biodiesel is a fuel produced from renewable resources through chemical transesterification using alkaline catalyst. Enzymatic synthesis of biodiesel is still expensive compared to the chemical process, but has the advantage of being more environmental-friendly. In this context, discovery of new lipases and utilization of low cost cultivation media are central to favor the economic viability of enzymatic biodiesel production. The aim of this study was to identify lipolytic strains among a large collection of microorganisms associated with plants. Fungi isolated from sugarcane (205), from Elaeis guineensis Jacq. (oil palm) (499) and from Jatropha curcas cake (72) were screened for lipase activity by qualitative tests in solid media containing triolein and olive oil as carbon source. Based on the results, we selected 32 fungi  for lipase production in solid state fermentation using mesocarp fiber from oil palm fruits. This substrate is a residue of palm oil production. For the cultivation, a mineral medium supplemented with glucose (1%) and  olive oil (5%) as carbon sources was added to the mesocarp fiber  to reach 60% humidity. The flaks were incubated at 28°C for 7 days. The highest yields of lipolytic activity were 8.3, 7.5 and 6.6 U of pNPP-hydrolyzing activity per gram of dry solids, obtained with the fungi cana175, 149A and 50A, respectively. These results can be promising for industrially relevant applications, since fungi lipase activities may be further improved by an optimization of processes conditions.