Crypthecodinium cohnii and Zymomonas mobilis syntrophy for production of omega 3 fatty acid

One of missions of industrial biotechnology is to produce valuable products from waste. In the current study we aim to establish a bioprocess of syntrophic co-cultivation of two microorganisms (Crypthecodinium cohnii and Zymomonas mobilis) at laboratory prototype level for bioconversion of renewables (molasses, the byproduct of sugar industry, and glycerol, byproduct of biodiesel production) into valuable vegetarian (produced by microorganisms) docosahexaenoic acid (DHA) from omega 3 fatty acid family. Cells of Z.mobilis strain (respiratory-deficient mutant derivative of the wild type strain Z.mobilis ATCC 29191) will be immobilized, following the previously described procedure of calcium alginate gel encapsulation. Mathematical modelling will be used for different components and at different stages of the syntrophic process to assist its improvement. The syntrophic bioprocess will be optimized with respect to (i) the medium composition, (ii) feed rates, (iii) oxygen supply, and (iv) the amounts of added immobilized Z. mobilis cells at particular stages of the fermentation. Genome and/or central carbon metabolism scale stoichiometric modelling and optimization will be performed to increase the utilization of cheap substrates and pre-treated residuals of C.cohnii. Bioprocess dynamics with respect to growth speed of batch fermentations will be modelled to ensure optimal proportions of syntrophic organisms, taking into account Z.mobilis production and immobilization as “slave” process of C.cohnii cultivation. Within several iterative cycles the fermentation data will be used for modelling and computer simulation of the bioprocess, and at the same time, the model-predicted dynamic behaviour of the system will aid further improvement of fermentation performance.publishersversionPeer reviewe

Model-based biotechnological potential analysis of Kluyveromyces marxianus central metabolism

Funding Information: The research was supported by ERDF project Nr. 2DP/2.1.1.1.0/14/APIA/VIAA/043. Publisher Copyright: © 2017, Society for Industrial Microbiology and Biotechnology.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 engineering. Modelling results imply that the aeration regime can be used as a tool to optimise product yield and flux distribution in K. marxianus. Also rebalancing NADH and NADPH utilisation can be used to improve the efficiency of substrate conversion. Xylose is identified as a biotechnologically promising substrate for K. marxianus.publishersversionPeer reviewe