Abstracts / Journal of Biotechnology 136S (2008) S402–S459 S447 V4-P-118 Accumulation of polyhydroxyalkanoates by starch-utilizing bacteria Sureelak Rodtong 1,∗ , Supavadee Songsrirote 1 , Chan- tima Deeprasertkul 2 , Nitinat Suppakarn 2 , Manote Sutheerawattananonda 3 1 Institute of Science,Suranaree University ofTechnology,Nakhon Ratchasima 30000, Thailand 2 Institute of Engineering, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand 3 Institute of Agricultural Technology, Suranaree University of Technol- ogy, Nakhon Ratchasima 30000, Thailand E-mail address: sureelak@sut.ac.th (S. Rodtong). Polyhydroxyalkanoates (PHA), a group of biopolymers, can consist of various hydroxyalkanoate monomers, and are synthesized and stored in the cell cytoplasm as water-insoluble inclusions by various microorganisms (Sudesh et al.,2000). The biopolymers are supe- rior to petrochemical-derived polymers in several aspects including biocompatibility, biodegradability, and both environmental and human compatibility. However, the widespread application of PHA has been hampered by high production cost. The use of cheap car- bon sources as bioconversion substrates could provide the cost reduction. In this study, cassava starch,one of the cheap carbon sources available, is of interest. Two hundred and eighty het- erotrophic bacterial strains isolated from their natural habitats in Thailand, were tested for their PHA accumulation and cassava starch utilization. The presence of intracellular PHA granules from 48-h cultures grown at 30 ◦ C, was examined by the amount of orange fluorescence after staining with Nile blue A ( Ostle and Holt, 1982) compared to Nile red dye (Berlanga et al., 2006) with some modifications to obtain the rapid screening, reliable, and simple method for bacterial PHA detection method.Twenty-two starch- utilizing isolates were found to accumulate different PHA contents estimated by the size of fluoresced bright orange granules. The maximum fluoresced bright orange with individual granule was visible within cells of five starch-utilizing strains. The identification of these bacteria and characterization of their biopolymers have been being investigated. These findings prevails that the bacterial strains have their potential for PHA production from cassava starch, a cheap carbon source. References Berlanga,M., Montero, M.T.,Hernández-Borrell,J., Guerrero,R., 2006. Rapid spec- trofluorometric screening of poly-hydroxyalkanoate-producing bacteria from microbial mats. Int. Microbiol. 9, 95–102. Ostle, A.G., Holt, J.G., 1982. Nile blue A as a fluorescent stain for poly-beta- hydroxybutyrate. Appl. Environ. Microbiol. 44, 238–241. Sudesh, K., Abe, H., Doi, Y., 2000. Synthesis, structure and properties of polyhydrox- yalkanoates: biological polyesters. Prog. Polym. Sci. 25, 1503–1555. doi: 10.1016/j.jbiotec.2008.07.1037 V4-P-119 Production of bacterialpolyhydroxyalkanoates for potential application Sureelak Rodtong 1,∗ , Chantima Deeprasertkul 2 , Niti- nat Suppakarn 2 , Weerasak Lertsiriyothin 2 , Manote Sutheerawattananonda 3 1 Institute of Science,Suranaree University ofTechnology,Nakhon Ratchasima 30000, Thailand 2 Institute of Engineering, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand 3 Institute of Agricultural Technology, Suranaree University of Technol- ogy, Nakhon Ratchasima 30000, Thailand E-mail address: sureelak@sut.ac.th (S. Rodtong). Polyhydroxyalkanoates (PHA) are carbon and energy reserve compounds accumulating intracellular as granules in certain bac- teria during unbalanced growth (Anderson and Dawes, 1990). The polymers have been recognized as better candidates for biodegradable plastics owing to their physico-chemical properties resembling petrochemical plastics and their complete biodegrad- ability (Luengo et al., 2003). Bacteria can synthesize a wide range of different PHA (Steinbuchel and Valentin, 1995). In this study, the production of bacterial PHA having properties for potential application was investigated. A Gram-negative bacterial strain iso- lated from its natural habitat and rapidly utilizing sugar extracted from sugar cane,was selected for PHA production by cultivating in a simple production medium containing carbon-nitrogen (C:N) ratio of 5:1 in a fermentor with 5-l working volume at 30 ◦ C for 48 h. The bacterial cells produced 18% PHA in their dry weight. The PHA yield could be increased by further optimization of cul- tivation process. The PHA produced by the selected strain, was easily extracted from the bacterial cells by using halogenated sol- vent 1,2-dichloroethane.Differential scanning calorimetry (DSC) thermograms showed melting temperature (T m ) and crystalliza- tion temperature (T c ) of the PHA at 168 and 71 ◦ C, respectively. The biopolymer had elastic property sufficient to yield high quality of plastic material.This preliminary study prevails that the selected bacterial strain has its capability to produce PHA having properties for potential application. References Anderson, A.J., Dawes, E.A., 1990. Occurence, metabolism, metabolic rate, and indus- trial uses of bacterial polyhydroxyalkanoates. Microbiol. Rev. 54, 450–472. Luengo, J.M., García, B., Sandoval, A., Naharro, G., Olivera, E.R., 2003. Bioplastics from microorganisms. Curr. Opin. Microbiol. 6, 251–260. Steinbuchel, A., Valentin, H., 1995. Diversity of bacterial polyhydroxyalkanoic acids. FEMS Microbiol. Lett. 128, 219–228. doi: 10.1016/j.jbiotec.2008.07.1038