Optimized Culture Medium And Fermentation Conditions For Lipid Production By Mulberry Endophytic Macrophomina Phaseolina MOD-1 And Lipid Production By Fungi Growing In Starch Processing Waste Water

Mulberry endophyte, which colonize in the healthy mulberry tissues without doing substantive harm to the host or gaining benefit other than securing residency, have successfully served as bioactivity agents in resent years. The results about studing on the endophyte and its secondary metabolites showed that plant endophyte could produce bioactivity metabolites. Up to now, no investigation was performed on mulberry endophytic fungi or its metabolites.Macrophomina phaseolina MOD-1, an endophytic oleaginous fungus isolated from the healthy mulberry root, which registration number is EU250575 on GenBank. Its lipid content was 22.72 %. This paper optimized medium composition and fermentation conditions for lipid production from strain MOD-1 and studied on microbial oils production by strain MOD-1 growing in starch processing waste water. The main results were showed as the followings:1. Optimize medium composition and fermentation conditions for lipid production by strain MOD-1. With single factor and uniform design were conducted, the study indicated that the best medium carbon source is starch, nitrogen source is polypeptone, inorganic salt is MnCl₂. The best medium recipe was found with starch 105 g/L, polypeptone 1.1 g/L, KH₂PO₄ 1.5 g/L, (NH₄)₂SO₄ 0.3 g/L, MgSO₄ 0.32 g/L, and MnCl₂ 4.9 nmol/L. The optimal fermentation conditions were as follows: initial pH 7.0, temperature 26℃, rotation speed 190 r/min and medium volume 100 mL, the medium was shaken for 6 d, and the dry cell weight was found as high as 41.852 g/L and lipid production was 25.511 g/L.2. Nine kinds of fatty acids were detected by GC-MS and the content of unsaturated fatty acids was 67.92 % after medium optimization. Seven kinds of fatty acids were detected and the content of unsaturated fatty acids was 74.32 % after fermentation optimization. The fatty acids producted by strain MOD-1 after optimization composite simply, tend to isolate and purify easily, and increase the content of unsaturated fatty acids.3. In this study, we research on using starch waste water to produce microbial oils by strain MOD-1, with the dry cell weight up to 2.218 g/L, lipid production and lipid content up to 1.005 g/L and to 45.33 % respectively. The COD reducing rate could achieve 30.68 %. Lipid production were improved by adding carbon source- starch. When the C/N is 50:1, the dry cell weight of strain MOD-1 was up to 35.773 g/L; lipid production and lipid content was up to 19.532 g/L and 54.60 % respectively while the removal rate of COD was up to 54.40 %. Seven kinds of fatty acids were detected and the content of unsaturated fatty acids was 70.823 % in this fermenting conditions. This paper indicated that obtaining microbial oils by starch waste water fermention while COD reducing is a practicable method.