Dependence on petroleum to sustain our current lifestyle has generated a myriad of pollutants that impose burdens on the natural environment, ranging from greenhouse gases and toxic by-products to plastics that may remain intact for centuries. More conventional manufacturing procedures use microbes as cell factories for the synthesis of biopolymers from renewable materials, whose biodegradability is critical to the reduction of plastic accumulation in nature. New DNA manipulation tools are constantly being developed and, together with our capacity to sequence the whole genome of host microbes, these tools have allowed us to unveil the metabolic capabilities of biopolymer-producing bacterial strains and to alter pathway function as well as genetic architecture. These approaches can now be rationally modified with the aim of both increasing the production of target products and tailoring the chemical structure of the biopolymer. In addition, biosynthetic genetic circuits can be designed and inserted into the biocatalyst to obtain novel biopolymers from different renewable carbon substrates.
To truly advance towards the complete replacement of conventional chemical processes based on petroleum, bioprocesses must first be developed and further optimized to a point where the natural or engineered bacterial strain performs at its best. With this, we will hopefully achieve the highest possible productivity of biopolymers by harnessing bioreactors that are guided by mathematical modeling and/or control. All these approaches are currently being applied for microbial synthesis of industrial biopolymers such as polyhydroxyalkanoates (PHAs), alginates, and polylactic acid (PLA), or building blocks of natural polymers like lactic, succinic, and adipic acid. The use of low cost substrates, or even waste materials, will have a substantial impact on the economics of biopolymer production and, overall, will eventually allow the rapidly evolving fields of industrial and systems biotechnology to contribute to a circular economy.