<i>Vibrio natriegens</i> is sensitive to its acidic fermentation products

Bioprocessing, the biological conversion of renewable resources into value-added chemicals, is poised to meet an increasing demand for sustainable alternatives to petroleum-based products. Many examples of bioprocessing feature anoxic fermentations that naturally maximize product formation relative to growth of the microbial catalyst. <i>Vibrio natriegens</i> is a facultatively fermentative bacterium that has gained attention for bioprocessing due to its rapid growth rate and ease of genetic engineering. However, the fermentative properties of <i>V. natriegens</i> have not been compared to traditional bioprocessing workhorses like <i>Escherichia coli</i>. We revealed that <i>V. natriegens</i> is comparatively sensitive to its own acidic fermentation products, likely because <i>V. natriegens</i> lacks acid resistance mechanisms possessed by <i>E. coli</i>. Thus, fermentative applications must address this sensitivity either by buffering the fermentations, engineering resistance mechanisms, or bypassing the sensitivity by engineering <i>V. natriegens</i> to produce neutral products.