Open Access Review Article Petroleum & Environmental Biotechnology Girdhar et al., J Pet Environ Biotechnol 2013, 4:5 http://dx.doi.org/10.4172/2157-7463.1000155 Volume 4 • Issue 5 • 1000155 J Pet Environ Biotechnol ISSN: 2157-7463 JPEB, an open access journal Abstract The ever increasing potentialities of petroleum plastics with respect to lack of degradation, inability to recycle and the toxic effects of incineration, has urged to design biodegradable polymers, often called Green Plastics. These biodegradable plastics are promiscuous due to their analogous properties and environmental friendliness. Bacterial factories and Plants being their natural sources for production made them a promiscuous solution. Fermentation is the procedural technology used with certain fillers that are known to enhance the chemo-mechanical properties. The process at the industrial level is not well accepted due to the certain lacunas. The review mainly focuses to assimilate a few researches that implicate the best known process parameters for Batch, Fed-batch, Continuous and Two stage modes of fermentation without compromising the downstream processing at commercial level. Process Parameters for Influencing Polyhydroxyalkanoate Producing Bacterial Factories: An Overview Amandeep Girdhar 1 *, Mayuri Bhatia 1 , Sunil Nagpal 2 , Amol Kanampalliwar 1 and Archana Tiwari 1 1 School of Biotechnology, Rajiv Gandhi Proudyogiki Vishwavidhyalaya, State Technological University, Airport Bypass Road, Bhopal 426033, Madhya Pradesh, India 2 Department of Biochemical Engineering, Indian Institute of Technology, Safdarganj Development Area, Hauz Khas, IIT Campus, New Delhi, Delhi 110016, India Keywords: Polyhydroxyalkanoate; Bacteria; Carbon sources; Batch culture; Economy Introduction In the world of advancements today, almost every product is constituted of some kind of polymer. ere is no doubt that the need for polymers and thus the products they constitute is ever increasing. Till date, these needs are being fulfilled by synthetic polymers (oſten called plastics), which are produced from petrochemicals [1] which makes them eco- ‘unfriendly’. e inherent nature of petroleum derived products, calls for a serving approach, in the form of Biopolymers- polymers derived from living organisms/renewable resources [2]. To satisfy the consumers and get acceptability substitute needs to exhibit similar (if not identical) characteristics to the product being replaced and so it is for biopolymers while replacing the synthetic polymers properties, ranging from molecular weight, density, melting point, crystallinity, glass transition temperature to O 2 -permeability, UV- resistance, resistance to solvents, tensile strength and elongation to break [3]. Fortunately, a special class of biopolymers called PHAs shows some of the extraordinary similarities to the well known synthetic polymers like polypropylene, polyethylene etc. [4], moreover, their biodegradability has made them renowned as biopolymers of today. History and chemical nature In 1920, a French microbiologist Maurice Lemoigne discovered a gram positive bacterium Bacillus megaterium [5] that accumulated intracellular granules of polyester called poly(3-hydroxybutyrate) [6]. Table 1 enlists different types of PHA. PHAs are polymeric compounds biosynthesized by a variety of gram positive and gram negative bacteria [7], as carbon and energy reserves (oſten called carbonosomes) [8]. Structurally, R-hydroxyalkonic acids act as the monomeric form of PHAs. Natural sources of production Polyhydroxyalkanoates are produced in microbes. Although efforts have been made from plant cells through transgenics, but has not achieved much success because low yields of less than 10 % (w/w) of dry cell weight can be sustained whereas, high yield limits growth and development of plants [9,10]. On the other hand, PHAs can be accumulated upto 90% (w/w) in bacterial cells [10] and are thus a priority because of the ease in culturing and economical, in contrast to the complex plant system [10]. Bacterial Polymer Production PHAs accumulation is an inherent response to the stress conditions faced by bacterial cells [11,12], these are generated in vitro by exposing bacteria to nutrient limitations, due to which they switch their metabolic pathways and cause PHA production as their carbon and energy reserves [13], to name a few of these substrates are bagasse [14], molasses [15,16], corn cob [14] and other agricultural wastes [4,17]. In fact significant PHA production has been reported among various bacterial strains when growing on kitchen waste [18], industrial wastes [7,14,19], crude and edible oils as carbon sources [20-23]. e costing of these substrates is low or null, making the process cost effective at the upstream level. e Figures 1 and 2 depicts the biopolymer synthesis from bacteria. PHA production has been reported in wide variety of bacterial *Corresponding author: Amandeep Girdhar, School of Biotechnology, Rajiv Gandhi Proudyogiki Vishwavidhyalaya, State Technological University, Airport Bypass Road, Bhopal 426033, Madhya Pradesh, India, Tel: +918989206617; E-mail: amangirdher@gmail.com Received August 19, 2013; Accepted September 26, 2013; Published October 03, 2013 Citation: Girdhar A, Bhatia M, Nagpal S, Kanampalliwar A, Tiwari A (2013) Process Parameters for Influencing Polyhydroxyalkanoate Producing Bacterial Factories: An Overview. J Pet Environ Biotechnol 4: 155. doi:10.4172/2157-7463.1000155 Copyright: © 2013 Girdhar A, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. PHAs Number of Carbon Atoms in Monomers of PHA Examples Short chain length PHAs (scl- PHAs) 3 – 5 P(3HB) P(4HB) Medium chain length PHAs (mcl-PHAs) 6 – 14 P(3HHx) P(3HO) P(3HHx-co-3HO) Table 1: Types of PHAs [2].