| Popis: |
L-lactate and 2, 3-butanediol are important chemicals used in many industries. Lactate is industrially produced by lactic acid bacteria, while Klebsiella bacteria are considered for the production of 2, 3-butanediol. However, these bioprocesses have certain disadvantages such as reliance on raw materials that could be used for human consumption or the use of potentially pathogenic bacteria. These disadvantages can be avoided by using a suitable microorganism and therefore the possibility of using the yeast Kluyveromyces marxianus for the production of L- lactate and 2, 3-butanediol was investigated in this study. K. marxianus is a non-conventional yeast that has some industrially important characteristics such as rapid growth rates, thermotolerance, ability to grow on xylose, and due to its GRAS status, it is also suitable for use in the food industry. To examine the potential of K. marxianus yeast for L-lactate production, a strain containing optimized genes encoding L- lactate dehydrogenase (ldhL) isolated from Lactobacillus gasseri was constructed. To study the production of 2, 3-butanediol, optimized genes encoding α-acetolactate synthase (alsS) and α- acetolactate decarboxylase (alsD) isolated from Bacillus subtilis were expressed in K. marxianus, and the effect of overexpression of native gene encoding 2, 3-butanediol dehydrogenase (BDH1) was examined. Wildtype yeast K. marxianus produces neither L-lactate nor 2, 3-butanediol when grown on glucose, while genetically modified strains produce up to 2, 5 g/L of L-lactate and about 4 g/L of 2, 3-butanediol. |
