Design of artificial bacteria-yeast consortia for production of protease, amylase, and lipase & optimization of process conditions

Enzymes are proteins that act as biocatalysts for many industrial processes. Among the hydrolytic enzymes, protease, amylase, and lipase have an important role due to their wide range of industrial applications. The bottleneck of enzyme technology is that its inability to meet industrial demand at a satisfactory and cost-effective rate. Enzyme cocktails have more precise regulation, faster and effectiveness in the degradation of complex substrates than individual enzymes. Besides, enzyme cocktail fermentations, rather than combining single enzymes, have advantages such as decreasing fermentation time and cost. Currently, several methods for improving enzyme production are available, including synthetic biology and statistical approaches based on single strain fermentations. However, the clarification of microbial interactions is still required to increase the productivity of the desired product. Microbial consortia, the coexistence of two or more microorganisms, is a promising approach that provides the opportunity for both concomitant production and high activity. This thesis aims to develop the concomitant production of the aforementioned three enzymes by artificial microbial consortia composed of bacteria and yeast families. The effect of microbial interaction on enzyme cocktail production was evaluated with two different consortia designs. In addition, the design and optimization of the factors affecting the enzyme cocktail production were carried out with the Response Surface Methodology. In this context, twenty different experiments were conducted using a quadratic polynomial model with Central Composite Design. As a result, both synergistic interactions of microorganisms and optimization of process conditions made it possible to improve fermentation performance.