Engineering Microorganisms to Produce Bio-Based Monomers: Progress and Challenges

Abstract

Bioplastics are polymers made from sustainable bio-based feedstocks. While the potential of producing bio-based monomers in microbes has been investigated for decades, their economic feasibility is still unsatisfactory compared with petroleum-derived methods. To improve the overall synthetic efficiency of microbial cell factories, three main strategies were summarized in this review: firstly, implementing approaches to improve the microbial utilization ability of cheap and abundant substrates; secondly, developing methods at enzymes, pathway, and cellular levels to enhance microbial production performance; thirdly, building technologies to enhance microbial pH, osmotic, and metabolites stress tolerance. Moreover, the challenges of, and some perspectives on, exploiting microorganisms as efficient cell factories for producing bio-based monomers are also discussed.

Designing biodegradable alternatives to commodity polymers

“…95,[99][100][101][102] Biobased monomers can also be produced in high yields and on large scales through the fermentation of genetically modified yeast and bacteria, with these approaches often presenting simpler purification processes compared to biomass extraction. [103][104][105] By using naturally occurring sources for raw materials rather than petroleum-derived chemicals, sustainability may be greatly increased as the monomers themselves can be renewably sourced and any degradation products will be much more likely to be completely mineralised.…”

Exploring the Role of Green Microbes in Sustainable Bioproduction of Biodegradable Polymers

“…Moreover, algae can grow on wastewater, which would reduce the cost of carbon, avoid the use of arable land that is suitable for agriculture for the production of sources of carbon for the production of biopolymers, and aid in the bioremediation of wastewaters through the removal of toxins. In addition to using waste as a source of energy and carbon for microorganisms and growing algae on wastewater to reduce the pressure on land, the cost of producing biopolymers can be lowered through the manipulation of carbon substrates into forms that can be used by different microorganisms using genetic engineering [38]. Genetic engineering has proven to be effective in the expansion of the substrate spectrum by enhancing substrates to enable the production of biopolymers and enhancing the properties of the biopolymers to be identical or close to the properties of synthetic polymers.…”

Metabolic Engineering of Microorganisms Towards the Biomanufacturing of Non-Natural C5 and C6 Chemicals

“…Cadaverine, or 1,5-diaminopentane is a straight-chain diamine that has shown to have many commercial applications, notably in bio-based materials, and is seen in chelating agents [89]. Cadaverine is naturally formed by bacterial decarboxylation of lysine that occurs during putrefaction of animal tissues.…”

“…In E. coli, the majority of studies focused on the bioconversion of lysine to cadaverine instead of a direct fermentative approach from glucose in order to avoid limitations of precursor availability and cell growth [89]. There are two main lysine decarboxylases (LDC) that can achieve this conversion: CadA and LdcC, both of which originate from E. coli.…”