Can Bio-plastics Replace Non-Biodegradable Plastics?

Abstract

Poly-3-hydroxybutyrate (PHB) is widely studied and best-characterized bioplastic within polyhydroxyalkanoates family, which can be used to produce a wide range of household and packaging products as well as medical products. Although biodegradable PHB is environmental friendly and not dependent on fossil resources, its production cost has been traditionally very expensive by bacterial fermentation techniques using recombinant E. coli. The recombinant diatoms and transgenic plants have also been evaluated for efficient PHB production. But, it has proved extremely difficult to increase the PHB yield that prohibits its production at the industrial scale. To address these problems, this paper has focused on the metabolic pathway manipulations in recombinant E. coli since they lack PHB degradation pathways unlike native producers. Another advantage of using recombinant E. coli is their ability to use a wide range cheap carbon sources, accumulate large amounts of polymers with higher productivity, maintain the high-cell density fermentation and recover the PHB easily. Since no single strategy has been proved to be sufficient enough to produce PHB industrially until today, the advanced and integrated approaches have to be considered for its efficient production in order to compete with non-biodegradable petrochemical plastics.

Economic and environmental assessment of bacterial poly(3-hydroxybutyrate) production from the organic fraction of municipal solid waste

“…Polyhydroxyalkanoates (PHAs) are aliphatic polyesters accumulated intracellularly by many prokaryotic organisms as carbon and energy storage in response to nutrient imbalance (Olaya-Abril et al 2017 ). PHAs form a large family of biodegradable bioplastics (Kabir et al 2017 ) which can be tailored to offer properties similar to those of several plastics manufactured from petroleum sources (Możejko-Ciesielska and Kiewisz 2016 ). In fact, polyhydroxyalkanoates have often been highlighted as competitors of petroleum-derived plastics due to their physical properties, biocompatibility and biodegradability, which makes them very attractive for the development of biomaterials such as, for instance, supports for protein immobilization (Bello-Gil et al 2018 ), a procedure long used for improving the performance of enzymatic reactions in many industrial applications (Alkorta et al 1996 , 1998 ).…”

Giving credit to residual bioresources: From municipal solid waste hydrolysate and waste plum juice to poly (3-hydroxybutyrate)

“…In particular, PHAs, which are produced as intracellular carbon/energy storage under nutrient limitation (of e.g. nitrogen, phosphorous or oxygen) by a large variety of microorganisms, are attracting much attention because they can be tailored so as to offer similar properties to petroleum-derived polymers and, in addition, are completely biodegradable (Kabir et al, 2017). It is worth to 5 mention that PHAs are the only bioplastics that are degradable in the marine environment (Rujnić-Sokele and Pilipović, 2017;DiGregorio, 2009).…”