Once cells have been used to produce biochemicals, there are only a few effective ways to utilize the residual cell mass, even though the utilization of leftover cells would aid in decreasing production costs. Here, a polyhydroxybutyrate (PHB) and isobutanol co-production system was designed to address this challenge. The addition of the PHB operon into Escherichia coli conferred a metabolic advantage for alcohol production, generating 1.14-fold more isobutanol. Furthermore, following nitrogen source optimization and cofactor engineering, the engineered E. coli strain produced 2-fold more isobutanol and 0.25 g/L PHB. Moreover, E. coli cells showed higher tolerance to isobutanol with the overexpression of PHB biosynthesis genes. This co-production system resulted in an increased biomass, higher glucose utilization, and lower acetate maintenance, leading to higher productivity regarding PHB and isobutanol yield. Thus, this novel system is applicable to future fermentation studies for the co-production of PHB and isobutanol.

一旦细胞已被用于生产生化试剂，即使剩余细胞的使用将有助于降低生产成本，也只有少数几种有效的方法可以利用细胞的残留量。在这里，设计了聚羟基丁酸酯（PHB）和异丁醇联产系统来应对这一挑战。在大肠杆菌中添加PHB操纵子可为酒精生产提供代谢优势，产生的异丁醇多1.14倍。此外，经过氮源优化和辅助因子工程设计，工程改造后的大肠杆菌菌株产生的异丁醇增加了2倍，PHB为0.25 g / L。此外，大肠杆菌随着PHB生物合成基因的过度表达，细胞对异丁醇的耐受性更高。该联产系统导致增加的生物量，更高的葡萄糖利用率和更低的乙酸盐维持率，从而导致PHB和异丁醇收率的更高生产率。因此，该新型系统可用于未来发酵研究，以共同生产PHB和异丁醇。