Is It Possible to Produce Polyhydroxyalkanoate (PHA) Bioplastics of Consistent Composition from Organic Wastes? A Review

The main aim of this paper is to address the available literature on the issue of controlling
the composition of polyhydroxyalkanoates (PHAs) during their production from organic
wastes and if possible, provide a complete strategy to achieve consistent composition.
Improvement in the handling of single-use packaging can result in tangible results in the
quality of everyday life and the reduction of pollution. PHA bioplastics are candidate
materials for many applications in the packaging sector. The cost of production of PHA
bioplastics can be reduced with the use of organic waste streams as feedstocks. However,
variations in the composition of the feedstock, result in variations in the composition of
the final product. Feasibility of organic wastes utilization to produce PHA bioplastic depends
on the ability to produce a consistent product-material. In this study, we focus on
methods developed and tested to produce consistent composition and properties of PHA
bioplastics from organic wastes. Numerous studies show that composition control can be
established without affecting the global productivity and yield. The critical stages for composition
control are the stages of feedstock selection, feedstock storage, and acidogenic
fermentation. Fine tuning of the PHA composition is possible by mixing or synthetic feed
in the stages of accumulation and extraction. Strategies for minimizing synthetic feed are
suggested for process viability. Though various studies have shown that it is possible to
obtain a consistent PHA material from organic wastes, strategies need to be developed to
achieve consistency without affecting productivity and yield.