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The production of biodegradable plastic from microorganisms has great potential as a substitute for conventional plastic. This study aims to isolate bacterial strains capable of polyhydroxyalkanoates (PHAs) production from the Kampung Jawa landfill land (KJLL) and characterize biopolymers. The bacterial strains were able to produce PHA using a mineral salt medium (MSM) with glucose as a carbon source. The qualitative screening of PHA-producing bacteria was conducted by Sudan Black and Nile Red. Of the 64 bacteria strains, only 41 were able to accumulate PHA in Sudan Black and Nile Red. The results showed that one bacteria the Coccobacillus strain had the highest color intensity for further characterization of PHA. The characterization of PHA by Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) showed a melting temperature (Tm) of 101.54°C. X-ray diffraction (XRD) analysis revealed a crystalline structure with an index crystallinity (ICr) value of 15.82% for PHA. The results of the analysis proved that PHA was produced by bacteria isolate. This study suggests that this is the first report of the bacteria from the Kampung Jawa landfill producing PHA with good characteristics and potential biotechnology applications.

Polyextremophiles have increasingly been utilised to produce thermostable enzymes with better stability in multiple extreme conditions. This study reports the screening results of four new bacterial isolates (PLS A, PLS 75, PLS 76 and PLS 80), isolated from an under water hot springs, in producing thermo-halostable protease enzyme. Optimum cultivation conditions for the protease production were also studied. Screening of protease-producing isolates was conducted using Thermus solid medium enriched with 3% skim milk and 0.5% casein. The growth of the isolates showing protease activity was monitored by measuring the cell dry weight and protease activity during 24 h cultivation period. The activity was also measured at various cultivation conditions, i.e. temperature, pH and salt concentrations. Amongst the four isolates, only PLS A showed the ability to produce protease. The optimum cultivation conditions for protease production were observed at 65°C, pH 7 for 18 h incubation. The activity increased with the addition of 1% NaCl concentration (0.085 Unit/mL). The ability of PLS A isolate to produce thermo-halostable protease was encouraging as they could potentially be used in industries requiring the enzyme with multiple extremes.

Exploitation of extremophiles as novel bioactive compounds sources has been increasing. The aim of this study was to evaluate the activity and the class of antibiotic produced by a thermo-halophilic isolate PLS 76, as well as to identify the genotype of the isolate. The activity was determined by a disc diffusion method, while the antibiotic class was determined qualitatively by chemical reactions using ninhydrin, iodine vapour and potassium iodine. The genotype was determined by sequencing the 16S rRNA gene fragment and the phylogenetic tree from the sequence data. The results showed that PLS 76 was a Gram-negative bacterium and able to produce polypeptide antibiotic, which showed a slight activity on E. coli and S. aureus. Sequence alignment of the 16S rRNA gene fragment showed that PLS 76 was most related to Geobacillus kaustophilus. These results may be used to utilise the isolated for further antibiotic study.