Transcriptomic analysis of synchrony and productivity in self-cycling fermentation of engineered yeast producing shikimic acid.

Industrial fermentation provides a wide variety of bioproducts, such as food, biofuels and pharmaceuticals. Self-cycling fermentation (SCF), an advanced automated semi-continuous fermentation approach, has shown significant advantages over batch reactors (BR); including cell synchrony and improved production. Here, Saccharomyces cerevisiae engineered to overproduce shikimic acid was grown under SCF operation. This led to four-fold increases in product yield and volumetric productivity compared to BR. Transcriptomic analyses were performed to understand the cellular mechanisms leading to these increases. Results indicate an up-regulation of a large number of genes related to the cell cycle and DNA replication in the early stages of SCF cycles, inferring substantial synchronization. Moreover, numerous genes related to gluconeogenesis, the citrate cycle and oxidative phosphorylation were significantly up-regulated in the late stages of SCF cycles, consistent with significant increases in shikimic acid yield and productivity.

Temperature, pH, and Glucose Responsive Gels via Simple Mixing of Boroxole- and Glyco-Based Polymers.

Statistical copolymers of N-isopropylacrylamide (NIPAAm) and 5-methacrylamido-1,2-benzoxaborole (MAAmBo) have been synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. The solution properties of the NIPAAm homopolymers and statistical copolymers were investigated and it was found that, besides temperature and pH, the statistical copolymers were also responsive to the presence of free glucose in solution. Furthermore, responsive hydrogels and nanogels were formed spontaneously by simply mixing the statistical copolymers of P(NIPAAm-st-MAAmBO)s and well-defined glycopolymers. These gels were found to have temperature, pH, and glucose responsive properties.