Optogenetic Modulation of a Catalytic Biofilm for the Biotransformation of Indole into Tryptophan

• Published in: ChemSusChem 2019-12, Vol.12 (23), p.5142-5148
• Main Authors: Hu, Yidan, Liu, Xiaobo, Ren, Aloysius Teng Min, Gu, Ji‐Dong, Cao, Bin
• Format: Article
• Language: English
• Subjects: biocatalysis; Biofilms; Bioreactors; Biotransformation; biotransformations; Catalysis; Chemical synthesis; Circuits; Culture Media; Cyclic GMP - genetics; Cyclic GMP - metabolism; enzymes; gene expression; Indoles - metabolism; Infrared radiation; Infrared Rays; Modulation; Optogenetics; Organic chemistry; Stability; Tryptophan; Tryptophan - biosynthesis
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.201902413

In green chemical synthesis, biofilms as biocatalysts have shown great promise. Efficient biofilm‐mediated biocatalysis requires the modulation of biofilm formation. Optogenetic tools are ideal to control biofilms because light is noninvasive, easily controllable, and cost‐efficient. In this study, a gene circuit responsive to near‐infrared (NIR) light was used to modulate the cellular level of bis‐(3′‐5′) cyclic dimeric guanosine monophosphate (c‐di‐GMP), a central regulator of the prokaryote biofilm lifestyle, which allowed the regulation of biofilm formation by using NIR light. The engineered biofilm was applied to catalyze the biotransformation of indole into tryptophan in submerged biofilm reactors and NIR‐light‐enhanced biofilm formation resulted in an approximately 30 % increase in tryptophan yield, which demonstrates the feasibility of the application of light to modulate the formation and performance of catalytic biofilms for chemical production. The c‐di‐GMP‐targeted optogenetic approach to modulate catalytic biofilms showcases applications for biofilm‐mediated biocatalysis. Bugs on film: A near‐IR‐light‐responsive, tryptophan‐producing Escherichia coli biofilm is engineered by introducing a near‐IR‐light‐responsive bis‐(3′‐5′) cyclic dimeric guanosine monophosphate (c‐di‐GMP) synthase and the genes that encode tryptophan synthase. In submerged biofilm reactors, near‐IR light enhances biofilm formation to result in an approximately 30 % increase in tryptophan yield.