MICROBIAL PRODUCTION OF POLYHYDROXYALKANOATES:CURRENT RESEARCH AND DEVELOPMENT

Petroleum product is the chief crude material for the production of synthetic plastic. Today these synthetic plastic materials become an integral part of our daily life because its low production cost and considerable durability. The uncontrolled utilization of these synthetic plastic materials by human beings is hazardous for the environment caused by their disposal as they are not decomposed by bacteria. The biodegradable biopolymers (PHAs) produced from various microorganisms will be a good candidate to replace the petroleum-derived plastics materials by establishment of cost-competitive production of these biopolymers from cheap r e newable resources. The development of feasible bioprocesses for the production of biodegradable plastics from cheap r e newable resources is possible on the utilization of food industry wastes, dairy waste and from agricultural residue as a substrate. The production of biodegradable plastics materials (PHAs) would be a great revolution in field of biotechnology as they are good substitute of petroleum derived plastics materials. The polyhydroxyalkanoates (PHAs) is a distinctive and most gorgeous biopolymer with a number of industrial and pharmaceutical applications have been studied broadly. Thermoplasticity and biodegradability of PHA have attracted considerable academic and industrial interest since past 20 years. In recent time many scientist works in this field are trying hard to employ and implement the strategy to produce PHAs economically. Approximately 150 hydroxyalkanoic acids other than 3-hydroxybutyrate (3HB) have been identified as constituents of PHA. The most commonly occurring PHA in bacteria is poly (3-hydroxybutyrate) (PHB), which has been commercialized under the trade name BIOPOL. Newly, a novel class of biopolymers, with thioester linkages in place of oxoester bonds, has been found in Ralstonia eutropha and has been classified as polythioesters. This review mainly focuses on the research and development of new PHAs-producing strains, utilization of renewable materials or industrial wastes, and high cell density culture technology for PHAs production.