Comparative analysis of the effects of hydrodynamic conditions in submerged culturing of recombinant bacteria

Abstract

Use of recombinant microorganisms in biotechnology is one of the leading branches of its development. Structure peculiarities of recombinant bacteria require the use of more sparing culturing conditions, first of all, stirring conditions. This requires more detailed study of the effects of hydrodynamic processes in fermenter, as well as mechanisms of this effect. Provided literature review contains analysis of studies of scientists worldwide in this area, devoted to the effects on biomass accumulation, synthesis of metabolites, and morphological structure of recombinant bacteria cells. As a result of the evaluation performed, we have arrived to the conclusion that, besides the stirring device rotation rate, the following factors exert essential effects: stirrer impeller structure, nutrient medium composition and pH, and aeration intensity, as well as the ratio between these parameters. In majority of cases, maximum metabolite synthesis conforms to maximum biomass increment, but this does not happen always; at high stirring rates, the change of external cellular structure and biosynthesis productivity decrease are observed. All these phenomena are related with development of shear stress in recombinant bacteria cells, but the mechanisms of this effect are not investigated in them. Thus, optimization of submerged culturing processes requires continued more detailed of the effects of hydrodynamic processes on recombinant bacteria growth and development.