Two sporulation-deficient B. subtilis strains (ΔspoIIE and ΔsigF) were successfully engineered using molecular cloning, PCR, and sequencing. These strains were transformed with an amylase-expressing plasmid and tested under 27 different culture conditions varying in glucose, raffinose, and yeast extract composition. Growth kinetics and enzyme secretion were monitored through optical density, amylase activity, and nutrient utilization assays.
Key findings include:
ΔspoIIE supported higher and more stable enzyme production than ΔsigF, validating early sporulation blockade as an effective strategy.
Optimal nutrient conditions (1% glucose + 2% yeast extract) balanced growth with secretion efficiency.
Raffinose acted as a secretion stabilizer rather than a primary carbon source, contributing to consistent enzyme titers.
Combined genetic and nutrient strategies provided a clear proof-of-concept for controlling bistability to enhance industrial enzyme production.
Deliverables achieved included construction and validation of mutant strains, comprehensive growth and secretion profiling, and identification of high-yield conditions. A manuscript is in preparation for submission to Microbial Cell Factories. Dissemination included a presentation at the Swammerdam Institute for Life Sciences seminar, and preliminary findings were integrated into other research lines within the host group.