Overconsumption of plastic goods and improper handling of petroleum-derived plastic waste have brought a plethora of negative impacts to the environment, ecosystem and human health due to its recalcitrance to degradation. These drawbacks become the main driving force behind finding biopolymers with the degradable properties. With the advancement in biopolymer research, polyhydroxyalkanoate (PHA) and poly(lacyic acid) (PLA) and its composites have been alluded to as a potential alternative to replace the petrochemical counterpart. This review highlights the current synthesis process and application of PHAs and PLA and its composites for food packaging materials and coatings. These biopolymers can be further ameliorated to enhance their applicability and are discussed by including the current commercially available packaging products. Factors influencing biodegradation are outlined in the latter part of this review. The main aim of this review article is to organize the scattered available information on various aspects of PHAs and PLA, and its composites for packaging application purposes. It is evident from a literature survey of about 140 recently published papers from the past 15 years that PLA and PHA show excellent physical properties as potential food packaging materials.

Polyhydroxybutyrate (PHB) is a biodegradable polyester synthesized as intracellular carbon and energy storage for numerous bacteria and archaea. PHB has been used extensively in biomedical industry. The gas chromatography (GC) method for PHB quantification has some drawbacks, such as large sample size required and involves tedious sample preparation. In this study, reactive pyrolysis-gas chromatography (reactive Py-GC) was applied to determine the PHB content in bacterial biomass. Bacillus sp. was cultured in mineral salts medium containing various concentrations of pretreated molasses (10 – 30 g/L) as a sole carbon source. The PHB content obtained by both methods; GC and reactive Py-GC were compared. The obtained PHB was cast into film and the physical properties was determined by DSC and TGA. The biodegradability of PHB film sample was performed by soil burial biodegradation test. Based on the peak intensities of reactive Py-GC analysis, the PHB contents were determined precisely and rapidly without any cumbersome sample pretreatment. Furthermore, the values of the PHB contents coincided overall with those obtained by the conventional GC method with correlation coefficient (R2) 0.9766. The melting temperature and degree of crystallinity were 172 °C and 61 %, respectively. The PHB film sample used in this study can biodegrade completely within 12 days.