Effect of vitreoscilla hemoglobin and culture conditions on production of bacterial L-asparaginase, an oncolytic enzyme.

L-asparaginase is a widely used cancer chemotherapy enzyme. The source for the enzyme with this property is mainly bacterial and its synthesis is strongly regulated by oxygen. In this study, we utilized two recombinant systems: one carried the gene (vgb) for the Vitreoscilla hemoglobin (VHb), a protein of prokaryotic origin which confers a highly efficient oxygen uptake to its host and the other carried the L-asparaginase gene (ansB).

Enhanced production of acetoin and butanediol in recombinant Enterobacter aerogenes carrying Vitreoscilla hemoglobin gene.

Microbial production of butanediol and acetoin has received increasing interest because of their diverse potential practical uses. Although both products are fermentative in nature, their optimal production requires a low level of oxygen. In this study, the use of a recombinant oxygen uptake system on production of these metabolites was investigated.

Genetic engineering of Enterobacter aerogenes with the Vitreoscilla hemoglobin gene: cell growth, survival, and antioxidant enzyme status under oxidative stress.

Hemoglobins in unicellular organisms, like the one here in the bacterium Vitreoscilla, have greater chemical reactivity than their homologues in multicellular organisms. They can catalyze redox reactions and may protect cells against oxidative stress. The ability of Vitreoscilla hemoglobin to complement deficiencies of terminal cytochrome oxidases in Escherichia coli also suggests that this hemoglobin can receive electrons during respiration.