4. Concluding remarks
This study describes the adaptation of the previously engineered phenylalanine-overproducing chassis P. taiwanensis GRC3 Δ8ΔpykA -tap to enable microbial production of bio-benzoic acid. The applied heterologous pathway converts phenylalanine viatrans -cinnamate to benzoate. Further, the catabolic versatility of Pseudomonas was exploited to establish novel pathways for the production of catechol and cis,cis -muconate. The catechol yields were relatively low compared to previously achieved production parameters for other aromatics, likely at least partially related to the high toxicity of catechol. However, the yields achieved for benzoate andcis,cis -muconate are very promising and future efforts should be made to increase the titers in a fed-batch fermentation. Benzoate has significant relevance as food preservative and as a starting point for the production of many other platform chemicals and secondary metabolites, thus expanding the product spectrum of P. taiwanensis as robust biotechnological workhorse.