Growth kinetic studies of Phoma macrostoma in lab-scale and establishment of process analytics

Abstract

Weeds significantly hinder food production by causing yield losses leading to widespread reliance on chemical herbicides for weed control. However, the environmental and health concerns associated with these chemicals, including soil microbiome disruption, resistance development, and potential health risks to humans, have led to a search for alternatives like “bioherbicides”. The filamentous fungus Phoma macrostoma emerges as a promising option, capable of selectively targeting broad-leaved weeds without persisting in the environment or posing significant risks to human health. This thesis tackles the challenge of improving the fermentation process of P. macrostoma by developing new analytical methods for substrate analysis and macrocidin extraction, with the goal of characterizing fermentation by determining P. macrostoma's growth kinetics as basis to optimize production and cultivation time for maximum yield with respect to macrocidins. The thesis could not establish a specific growth rate due to challenges in tracking biomass accurately. However, it was successful in recording sugar consumption, macrocidin production, CFU and offgas data. Methods were developed to measure substrate concentration using a glucose meter and to improve the extraction method for macrocidin, increasing its yield but without conclusive evidence of reducing variability. Quantitative growth data was successfully gathered, suggesting that shorter fermentation periods than four weeks could reduce macrocidin yield.