Genome Shuffling of Mangrove Endophytic Aspergillus luchuensis MERV10 for Improving the Cholesterol-Lowering Agent Lovastatin under Solid State Fermentation

In the screening of marine mangrove derived fungi for lovastatin productivity, endophytic Aspergillus luchuensis MERV10 exhibited the highest lovastatin productivity (9.5 mg/gds) in solid state fermentation (SSF) using rice bran. Aspergillus luchuensis MERV10 was used as the parental strain in which to induce genetic variabilities after application of different mixtures as well as doses of mutagens followed by three successive rounds of genome shuffling. Four potent mutants, UN6, UN28, NE11, and NE23, with lovastatin productivity equal to 2.0-, 2.11-, 1.95-, and 2.11-fold higher than the parental strain, respectively, were applied for three rounds of genome shuffling as the initial mutants. Four hereditarily stable recombinants (F3/3, F3/7, F3/9, and F3/13) were obtained with lovastatin productivity equal to 50.8, 57.0, 49.7, and 51.0 mg/gds, respectively. Recombinant strain F3/7 yielded 57.0 mg/gds of lovastatin, which is 6-fold and 2.85-fold higher, respectively, than the initial parental strain and the highest mutants UN28 and NE23. It was therefore selected for the optimization of lovastatin production through improvement of SSF parameters. Lovastatin productivity was increased 32-fold through strain improvement methods, including mutations and three successive rounds of genome shuffling followed by optimizing SSF factors.

Active enhancement of bacillus thuringiensis subspisraelensis toxins and protein-purification

Bacillus thuringiensissub sp. ilsraelensis de Barjac, that produce insecticidal protein endotoxins are used for mosquito control. The bacterium produces several cry and cytoxins that individually show activity against mosquitoes. A CryllA protein IA848, which corresponds to the first 848 amino acids from N-terminal of CryllA-gene was purified from E.coli by Ni-NTA affinity isolation, Q-Sepharose Fast-Flow chromatography and Super-200 size exclusion chromatography. It was determined using laboratory bioassays that the purified-IA848 protein has good insecticidal competitive binding bioassays show that IA848 does not compete with CryIAb for binding to the brush border membrane vesicles [BBM] of the Aedesaegyptiborer and does not compete with CryIAb at concentrations below 400-fold excess of un-labeled CrylAb for binding to the peritrophic matrix [PM] of the insect. This IA848 proved good competitive in control strategies. CryllA protein purification demonstrate molecular mechanism by which CytIA synergizes or suppresses resistance to toxins by providing a binding site for CryIIAa that resulted in an efficient formation of CryIIAa pre-pore that inserts into membranes and forms'fonic pores