Translocation of Zymomonas mobilis pyruvate decarboxylase to periplasmic compartment for production of acetaldehyde outside the cytosol

Abstract Acetaldehyde, a valuable commodity chemical, is a volatile inhibitory byproduct of aerobic fermentation in Zymomonas mobilis and in several other microorganisms. Attempting to improve acetaldehyde production by minimizing its contact with the cell interior and facilitating its removal from the culture, we engineered a Z. mobilis strain with acetaldehyde synthesis reaction localized in periplasm. For that, the pyruvate decarboxylase (PDC) was transferred from the cell interior to the periplasmic compartment. This was achieved by the construction of a Z. mobilis Zm6 PDC‐deficient mutant, fusion of PDC with the periplasmic signal sequence of Z. mobilis gluconolactonase, and the follow…

Whey lactose bioconversion to valuable products by non-conventional yeasts Kluyveromyces marxianus

Model-based biotechnological potential analysis of Kluyveromyces marxianus central metabolism

Abstract The non-conventional yeast Kluyveromyces marxianus is an emerging industrial producer for many biotechnological processes. Here, we show the application of a biomass-linked stoichiometric model of central metabolism that is experimentally validated, and mass and charge balanced for assessing the carbon conversion efficiency of wild type and modified K. marxianus. Pairs of substrates (lactose, glucose, inulin, xylose) and products (ethanol, acetate, lactate, glycerol, ethyl acetate, succinate, glutamate, phenylethanol and phenylalanine) are examined by various modelling and optimisation methods. Our model reveals the organism’s potential for industrial application and metabolic engi…

Utilization of different carbohydrates by various Kluyveromyces marxianus strains