Model-based Analysis and Optimisation of a Continuous Corynebacterium glutamicum Bioprocess Utilizing Lignocellulosic Waste
Abstract Lignocellulosic waste streams are an important sustainable alternative to conventional carbon sources for industrial biotechnology. However, lacking quantitative knowledge on cultivation behavior hampers process design and optimization. Using an unstructured kinetic model describing the growth of wild-type Corynebacterium glutamicum on a lignocellulosic waste stream from pulping industry, we designed a continuous fermentation process with an optimized space time yield for biomass of 0.86 g L-1 h-1 and a residual concentration of metabolizable sugars in the effluent of less than 2 %. The model considers the growth on multiple interacting sugars and potentially inhibitory effects of lignocellulosic waste. After parametrization on historical data, the model was used to determine optimal setpoints of dilution rate and feed medium concentration. Sensitivity analysis of the model provided additional information on the importance of certain parameters during different process conditions and detected bottlenecks of strain physiology limiting the process design space. This model-based approach delivers valuable insights for process and strain engineering already at an early stage of bioprocess development.