Increasing Solvent Tolerance to Improve Microbial Production of Alcohols, Terpenoids and Aromatics

• Main Authors: Thomas Schalck, Bram Van den Bergh, Jan Michiels
• Format: Article
• Language: English
• Published: MDPI AG 2021-01-01
• Series: Microorganisms
• Subjects: product toxicity; stress-response pathways; solvent tolerance; yeast; bacteria; bioproduction
• Online Access: https://www.mdpi.com/2076-2607/9/2/249

Fuels and polymer precursors are widely used in daily life and in many industrial processes. Although these compounds are mainly derived from petrol, bacteria and yeast can produce them in an environment-friendly way. However, these molecules exhibit toxic solvent properties and reduce cell viability of the microbial producer which inevitably impedes high product titers. Hence, studying how product accumulation affects microbes and understanding how microbial adaptive responses counteract these harmful defects helps to maximize yields. Here, we specifically focus on the mode of toxicity of industry-relevant alcohols, terpenoids and aromatics and the associated stress-response mechanisms, encountered in several relevant bacterial and yeast producers. In practice, integrating heterologous defense mechanisms, overexpressing native stress responses or triggering multiple protection pathways by modifying the transcription machinery or small RNAs (sRNAs) are suitable strategies to improve solvent tolerance. Therefore, tolerance engineering, in combination with metabolic pathway optimization, shows high potential in developing superior microbial producers.