Curated Optogenetic Publication Database

Abstract: Microbial coculture can integrate advantages and overcome the metabolic imbalance of individual species. Programming strain interactions represents a common routine for synthetic microbial communities with distinct species, which causes difficulties and redundant workloads in interaction construction before being available as chassis hosts. This study explores yeast-bacterium consortium without engineered interactions for the co-inducible relayed synthesis of natural products. The Komagataella phaffii-Escherichia coli consortium is explored for co-growth under selected conditions. Low-level glucose- and blue light-responsive transcriptional systems are rebuilt separately for each host, allowing single-signal co-induced activation of compound synthesis in coculture. Pathway redirection, genome mining, and rewiring of key targets for acyl donor degradation result in efficient production of the reporter molecule simvastatin (26.2 mg l-1) through living consortium cultured on simple carbon source. Inducible biosynthesis of another reporter compound (2S)-naringenin (165.6 mg l-1) further validates the extendibility of this community. The described platform represents a breakthrough in engineering microbial consortium for biosynthesis.

Abstract: Komagataella phaffii, also known as Pichia pastoris, is a powerful host for recombinant protein production, in part due to its exceptionally strong and tightly controlled PAOX1 promoter. Most K. phaffii bioprocesses for recombinant protein production rely on PAOX1 to achieve dynamic control in two-phase processes. Cells are first grown under conditions that repress PAOX1 (growth phase), followed by methanol-induced recombinant protein expression (production phase). In this study, we propose a methanol-free approach for dynamic metabolic control in K. phaffii using optogenetics, which can help enhance input tunability and flexibility in process optimization and control. The light-responsive transcription factor EL222 from Erythrobacter litoralis is used to regulate protein production from the PC120 promoter in K. phaffii with blue light. We used two system designs to explore the advantages and disadvantages of coupling or decoupling EL222 integration with that of the gene of interest. We investigate the relationship between EL222 gene copy number and light dosage to improve production efficiency for intracellular and secreted proteins. Experiments in lab-scale bioreactors demonstrate the feasibility of the outlined optogenetic systems as potential alternatives to conventional methanol-inducible bioprocesses using K. phaffii.

Abstract: Pichia pastoris (P. pastoris) is the workhorse in the commercial production of many valuable proteins. Traditionally, the regulation of gene expression in P. pastoris is achieved through induction by methanol which is toxic and flammable. The emerging optogenetic technology provides an alternative and cleaner gene regulation method. Based on the photosensitive protein EL222, we designed a novel "one-component" optogenetic system. The highest induction ratio was 79.7-fold under blue light compared to the group under darkness. After switching cells from dark to blue illumination, the system induced expression in just 1 h. Only 2 h after the system was switched back to the darkness from blue illumination, the target gene expression was inactivated 5-fold. The induction intensity of the optogenetic system is positively correlated with the dose and periodicity of blue illumination, and it has good spatial control. These results provide the first credible case of optogenetically induced protein expression in P. pastoris.