Purification and biochemical characterization of a novel ene- reductase from Kazachstania exigua HSC6 for dihydro-β-ionone from β-ionone.

Purpose: We purified and characterized a novel ene-reductase (KaDBR1) from Kazachstania exigua HSC6 for the synthesis of dihydro-β-ionone from β-ionone.

Methods: KaDBR1 was purified to homogeneity by ammonium sulfate precipitation and phenyl-Sepharose Fast Flow and Q-Sepharose chromatography. The purified enzyme was characterized by measuring the amount of dihydro-β-ionone from β-ionone with LC-MS analysis method.

A novel thermophilic β-carotene 15,15'-monooxygenase with broad substrate specificity from the marine bacterium Candidatus Pelagibacter sp. HTCC7211.

To characterize a novel thermophilic β-carotene 15,15'-monooxygenase BCMO isolated from the marine bacterium Candidatus Pelagibacter sp. HTCC7211. BCMO was functionally overexpressed in Escherichia coli and purified to homogeneity by Ni-NTA affinity chromatography and Superdex-200 gel filtration chromatography.

Enhancing production of L-serine by increasing the glyA gene expression in Methylobacterium sp. MB200.

Microbial fermentation using methylotrophic bacteria is one of the most promising methods for L-serine production. Here we describe the metabolic engineering of a Methylobacterium strain to increase the production of L-serine. The glyA gene, encoding serine hydroxymethyltransferase (SHMT), was isolated from the genomic DNA of Methylobacterium sp.

Isolation and characterization of an operon involved in sulfate and sulfite metabolism in Sinorhizobium fredii.

A gene cluster ORFabcd from a Sinorhizobium fredii HN01 mutant strain HSMRalpha was isolated. We showed that it was an operon involved in sulfur metabolism. Functional studies revealed that, except for ORFb, the three genes ORFa, ORFc and ORFd were involved in sulfite reduction.

Significant improvement of Serratia marcescens lipase fermentation, by optimizing medium, induction, and oxygen supply.

Production of an extracellular lipase from Serratia marcescens ECU1010, which is an industrially important biocatalyst for the stereospecific synthesis of Diltiazem precursor, was carefully optimized in both shake flasks and a fermenter, using Tween-80 as the enzyme inducer. Dextrin and beef extract combined with ammonium sulfate were indicated to be the best carbon and nitrogen sources, respectively. With the increase of Tween-80 from 0 to 10 g l-1, the lipase production was greatly enhanced from merely 250 U l-1 to a maximum of 3,340 U l-1, giving the highest lipase yield of ca 640 U g-1 dry cell mass (DCW), although the maximum biomass (6.