2025/04/01 by Nuran Temelli, SA Akker, Ruud A. Weusthuis +1 · 1 voice
Biochemistry, Genetics and Molecular Biology · #Fungal and yeast genetics research #Microbial Metabolic Engineering and Bioproduction #Viral Infectious Diseases and Gene Expression in Insects
paper · pdf · doi:10.1111/1751-7915.70126
openalex publication_date 2025/04/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/26
In many microbial biotechnology processes, biomass itself is not the product of interest, but rather targeted chemicals or proteins. In these processes, growth should be limited to direct more substrate to product and increase process yields. Under growth-limiting conditions, such as nutrient limitation, microorganisms, including the yeast Saccharomyces cerevisiae, activate a general stress response (GSR). Different hypotheses have been formulated for this activation, including a preparatory role for future stresses or a role in cellular protein density. Here we tested a third hypothesis: the GSR reduces the energy needed to maintain cellular homeostasis, also known as the maintenance energy requirement (MER). The impact of GSR on MER was investigated by assessing the effect of the absence of its key regulators, Msn2 and Msn4, on energy-substrate distribution and stress resistance. Chemostat and fed-batch cultures revealed significant increases in MER of up to 85% in the deletion strain compared to the parental strain. In contrast, maximal biomass yields, growth rates and morphology were unaffected. Our insights highlight an additional role of the GSR, namely saving cellular energy. As the MER is a key determinant of product yields and in process design, especially in low growth processes, our findings can help to optimise microbial bioprocesses.