A strain of Bacillus sp. (112A) showed intracellular inclusion bodies when grown in the presence of molasses. The inclusion bodies were stained with Nile blue suggesting polyhydroxyalkanoates (PHA). The Bacillus sp. 112A strain produced PHA at different concentration of molasses as carbon source. The highest amount of PHA produced was 1.9 g/L in the presence of 1% molasses as carbon substrate in the medium. This strain also produced PHA under nitrogen, potassium, sulphur and phosphate limiting conditions, where it could produce high amount of PHA under nitrogen limiting condition than other limiting conditions. The produced polymer was extracted, quantified and later analyzed by GC and TEM, where TEM showed not all the cells contained heavy PHA bodies, suggesting the potential for increasing the overall yield.

The problem of environmental pollution caused by indiscriminate dumping of plastic waste has assumed global proportions. These conventional plastics that are synthetically derived from petroleum are not readily biodegradable (Young, 1981; and Huang et al., 1991) and are harmful wastes. In search of environment-friendly materials to substitute for conventional plastics, different biodegradable plastics have been developed either by incorporating natural polymers into conventional plastics, by chemical synthesis, or by microbial fermentations (Chang, 1994; and Chau et al., 1995), or else isolated and extracted from natural organisms of different ecosystems.

Polyhydroxyalkanoic acids (PHA) are common intracellular granules found in prokaryotes. PHA are biodegradable polymers with properties that may be of use as bulk commodity plastics. PHA can be produced biologically from renewable resources. The main hindrance in the use of PHA is their cost of production. Bacteria produce PHA as an intracellular carbon and energy storage material by various pathways (Dawes and Senior, 1973; Anderson and Dawes, 1990; and Verlinden et al., 2007). There is a great interest in developing optimum PHA producing organisms for inexpensive production.

Different species of bacteria produce different amounts of PHA. In minimal media containing 10 g/L soybean oil, Pseudomonas stutzeri 1317 produced up to 63% PHA containing a novel monomer of 3, 6 epoxy 7 nonene – 1, 9, dioic acids together with minor monomer of C8 and C10 (Wennan et al., 1998). P. cepacia accumulated PHB (Polyhydroxybutyrate, a simple PHA) in excess of ~50% of the dry weight of its biomass (Ramsay et al., 1989). PHA produced by a strain of Serratia sp. was maximally 55% of stored material per g of biomass dry weight (Harriet et al., 2008).

Commercial PHB production is still limited by economic constraints; the threshold for commercial feasibility is ~50% of the cell mass as PHB. Considerable effort was invested in the development of improved fermentation and processing methods (Choi and Lee, 1997).

Thick gram positive cell wall makes the PHB extraction process difficult. This may be one of the reasons for the fact that no Bacillus strains have been used for PHB production purposes (Qiong et al., 2001). So far, less detailed investigation on PHB formation by Bacillus spp. under high ratios of carbon to nitrogen or carbon to phosphorus and low oxygen supply has been reported.

The organism used in the present study, a strain of Bacillus sp. was shown to grow economically on agricultural wastes (Thirumala et al., 2009a). In this paper, Bacillus sp. strain 112A was used as a model to study PHA synthesis in Bacillus using molasses as a carbon source, derived from sugarcane industry as a waste product. This strain has the ability to grow aerobically in high concentrations of substrate and has tolerance to higher temperatures.

Biotechnology Journal, Stress Adaptation of Bacteria, Extremophiles, Bacterial Adaptation, Cytosolic Components, Denature Cellular Proteins, Reactive Oxygen Species, Monounsaturated Fatty Acids, Ultraviolet Radiation, Environmental Stress, Stress Management, Biological Systems, Cellular Economy.