The following study was conducted by Scientists from Department of Life Sciences, Imperial College London, United Kingdom. Study is published in Proceedings of the National Academy of Sciences Journal as detailed below.
Proceedings of the National Academy of Sciences (2020); 117(3): 1404-1413
Bioderivatization As a Concept for Renewable Production of Chemicals That are Toxic or Poorly Soluble in the Liquid Phase
Significance
Microorganisms can be rationally engineered to convert CO2 and H2O into chemicals, replacing those made from fossil fuels today. Sometimes such chemicals are poorly soluble in water or negatively affect the growth of the microorganism, resulting in cost-inefficient manufacturing. In nature, this problem is often solved by converting incompatible chemicals into those more compatible with the host and/or environment. Inspired by this, we propose a similar strategy for engineered biotechnology, whereby biochemical conversion inside the microorganism is followed by chemical reversal once outside. The principle was demonstrated with 1-octanol by implementing two different conversion methods in two different species, showing enhanced bioproduction in most cases. The approach may stimulate commercialization of sustainable and renewable production of chemicals.
Abstract
Bio-based production technologies may complement or replace petroleum-based production of chemicals, but they face a number of technical challenges, including product toxicity and/or water insolubility. Plants and microorganisms naturally biosynthesize chemicals that often are converted into derivatives with reduced toxicity or enhanced solubility. Inspired by this principle, we propose a bioderivatization strategy for biotechnological chemicals production, defined as purposeful biochemical derivatization of intended target molecules. As proof of principle, the effects of hydrophobic (e.g., esterification) and hydrophilic (e.g., glycosylation) bioderivatization strategies on the biosynthesis of a relatively toxic and poorly soluble chemical, 1-octanol, were evaluated in Escherichia coli and Synechocystis sp. PCC 6803. The 1-octanol pathway was first optimized to reach product titers at which the host displayed symptoms of toxicity. Solvent overlay used to capture volatile products partially masked product toxicity. Regardless of whether solvent overlay was used, most strains with bioderivatization had a higher molar product titer and product yield, as well as improved cellular growth and glucose consumption, compared with strains without bioderivatization. The positive effect on bioproduction was observed with both the hydrophobic and hydrophilic strategies. Interestingly, in several combinations of genotype/induction strength, bioderivatization had a positive effect on productivity without any apparent effect on growth. We attribute this to enhanced product solubility in the aqueous or solvent fraction of the bioreactor liquid phase (depending on the derivative and medium used), with consequent enhanced product removal. Overall, under most conditions, a benefit of bioproduction was observed, and the bioderivatization strategy could be considered for other similar chemicals as well.
Source:
Proceedings of the National Academy of Sciences
URL: https://www.pnas.org/content/117/3/1404
Citation:
Sattayawat, P., I. S. Yunus, et al. (2020). “Bioderivatization as a concept for renewable production of chemicals that are toxic or poorly soluble in the liquid phase.” Proceedings of the National Academy of Sciences 117(3): 1404-1413.
