Production and Applications of Crude Polyhydroxyalkanoate-Containing Bioplastic from the Agricultural and Food-Processing Wastes

The nondegradable petrochemical plastics are accumulated in the environment at an annual rate of about 25 million tons. Therefore, there are considerable economic and environmental interests in the development of biodegradable plastic polyhydroxyalkanoates (PHAs) produced by bacteria. However, the cost of this bioplastic, produced by conventional technologies, is several times higher than the cost of petrochemical-based plastics. The suitable ways for the reduction of the bioplastic production costs are as follows: (1) use of cheap raw materials such as organic wastes, (2) low-cost biotechnologies, and (3) production of crude bioplastic for specific applications. The following options for raw materials, biotechnologies, and applications of crude bioplastic are suitable: (1) use of food-processing or agricultural wastes for bioplastic production; (2) batch or continuous non-aseptic cultivation for the biosynthesis of bioplastic by mixed bacterial culture; (3) concentration and extraction of bioplastic using chemical treatment, filtration, centrifugation, and flotation for the production of crude bioplastic; and (4) applications of crude (not extracted) biodegraded bioplastic in the construction industry and agriculture. The implementation of these findings in the manufacturing process of PHA-containing bioplastic would significantly reduce production costs, thereby rendering PHA-containing bioplastic an economically viable and environmentally friendly alternative to petrochemical-based plastics.