Production of Bioplastic Compounds by Genetically Manipulated and Metabolic Engineered Cyanobacteria

Abstract

Direct conversion of carbon dioxide to valuable compounds is a desirable way to reduce the environmental burden and switch from fossil to renewable fuels. Cyanobacteria are photosynthetic bacteria that perform oxygenic photosynthesis and are able to produce valuable compounds from carbon dioxide in the air. Synechocystis and Synechococcus species, model unicellular cyanobacteria, can produce succinate and lactate, which are commodity chemicals used to generate bioplastics. Several cyanobacteria are also able to produce polyhydroxybutyrate, a biodegradable polyester that accumulates under nitrogen or phosphorus starvation. Genetic manipulation succeeded in increasing the productivity of succinate, lactate, and polyhydroxybutyrate from cyanobacteria. We summarize the recent findings in this review.

Development of Clostridium tyrobutyricum as a Microbial Cell Factory for the Production of Fuel and Chemical Intermediates From Lignocellulosic Feedstocks

“…However, the butyrate biosynthetic pathway is a key ATP-generating route in C. tyrobutyricum; thus, flux rewiring could be ATPlimiting. Acetoacetyl CoA, and the downstream conversion intermediate 3-hydroxybutyryl-CoA, also present precursors for the biosynthesis of (poly)hydroxybutyrate (PHB), itself a precursor for a range of polymer and biodegradable plastics (Katayama et al, 2018). For example, an alternative biosynthetic route to 3-hydroxybutyrate (3HB) entails incorporation of phosphor-transbutyrylase (ptb) and butyrate kinase (buk) genes, which diverts flux from 3-hydroxybutyryl-CoA to enable two-step conversion to 3HB via a 3HB-P intermediate, notably generating ATP en route to 3HB.…”

Bioprocess Engineering Aspects of Sustainable Polyhydroxyalkanoate Production in Cyanobacteria

“…However, these attempts have rarely shown success regarding increased volumetric or specific polymer content for commercial production of cyanobacterial PHB. Recently, Katayama et al reviewed the production of bioplastic compounds using genetically modified and metabolically engineered cyanobacteria [47]. In this study, we provide a list of genetically modified cyanobacteria with their PHB content and the tools used for the metabolic engineering of the strain.…”

“…The resulting recombinant Synechhocytis sp. PCC 6803 showed increased PHA synthase activity; the total PHB content, however, did not increase [47,54]. For cyanobacterial strain Synechocystis sp.…”

An Improved Natural Transformation Protocol for the Cyanobacterium Synechocystis sp. PCC 6803

“…Exogenous DNA molecules introduced into Synechocystis via natural transformation may replicate independently on a suitable plasmid (Mermet-Bouvier et al, 1993) or be incorporated into the genome via double homologous recombination (Grigorieva and Shestakov, 1982;Shestakov et al, 1985). As such Synechocystis is widely used in the field of biotechnology with engineered strains producing a variety of industrially relevant chemical commodities (Xue and He, 2018;Katayama et al, 2018;Gale et al, 2019).…”