Poly-hydroxybutyrate (PHB) production by Halomonas elongata BK AG 18 indigenous from salty mud crater at central Java Indonesia

Aims: Bioplastic is a biodegradable polymer produced by particular microorganism as a secondary metabolite. Some halophilic bacteria belonging to Halomonas genus have been reported to be a potential of polyhydroxybutyrate (PHB) producer. This study aims to explore the potential of an indigenous halophilic bacterial isolate, H. elongata BK-AG18, as bioplastic producer. The indication as bioplastics producer was evaluated by growing in nile red-containing medium and bacterial colonies displayed bright orange fluorescent under ultraviolet light. Methodology and results: Bioplastic production by H. elongata BK-AG 18 was achieved using modified glucosecontained High Medium (HM) after incubated in a rotary shaker for 22 h, 37 °C, 150 rpm. The bioplastic was extracted with chloroform and sodium hypochlorite (1:1) and precipitated in methanol. The highest yield of bioplastic production was 21.36% of the dried bacterial cell weight. The structural characterizations of the bioplastics using Fourier transformed infrared (FTIR), 1H and 13C nuclear magnetic resonances (NMR) spectroscopies showed high similarity to the spectral pattern of poly-hydroxybutyrate (PHB). Further characterization using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) revealed that the decomposition and melting temperature at 266 °C and 166.5 °C of the PHB, respectively. The result of PHB has a low degree of crystallinity (9.5%) that close to the rubber-like polymer. Conclusion, significance and impact of study: This study revealed the high potential of H. elongata BK-AG 18 as PHB producer with high mechanical properties.

Microspheres prepared with biodegradable PHBV and PLA polymers as prolonged-release system for ibuprofen: in vitro drug release and in vivo evaluation

In this study, poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) and poly(l-lactide) (PLA) microspheres containing ibuprofen were prepared with the aim of prolonging the drug release. The oil-in-water (O/W) emulsion solvent evaporation technique was used, varying the polymer ratio. All formulations provided spherical particles with drug crystals on the surface and a porous and rough polymeric matrix when PHBV was used and smooth external surface when prepared with PLA. The in vitro dissolution profiles show that the formulation containing PHBV/PLA at the proportion of 30/70 presented the best results in terms of prolonging the ibuprofen release. The analysis of the concentration of ibuprofen in the blood of rats showed that maximum levels were achieved at between one and two hours after administration of the immediate-release form (pure drug), while the prolonged microspheres led to a small amount of the drug being released within the first two hours and reached the maximum level after six hours of administration. It was concluded that it is possible to prolong the release of ibuprofen through its incorporation into PHBV/PLA microspheres.

No presente estudo foram preparadas microesferas de poli(hidroxibutirato-co-hidroxivalerato) (PHBV) e poli(ácido láctico) (PLA) com o objetivo de prolongar a liberação do ibuprofeno, utilizado como fármaco modelo. Empregou-se o método de emulsificação e evaporação do solvente óleo em água (O/A), variando-se a proporção entre os polímeros. Todas as formulações originaram partículas esféricas com cristais de fármaco aderidos à superfície externa. As microesferas apresentaram superfície rugosa e porosa, quando o PHBV foi utilizado, e superfície externa lisa, quando preparadas com o PLA. Os perfis de dissolução in vitro evidenciaram que a formulação que continha PHBV/PLA na proporção de 30/70 apresentou melhores resultados para prolongar a liberação do ibuprofeno. Através da análise da concentração de ibuprofeno no plasma de ratos, após administração oral, verificou-se que os níveis máximos ocorreram entre 1 e 2 horas após a administração de ibuprofeno não encapsulado, enquanto o fármaco presente nas microesferas atingiu um pico máximo após 6 horas da administração. Conclui-se, portanto, que é possível prolongar a liberação do ibuprofeno após a sua incorporação às microesferas preparadas com os polímeros PHBV e PLA, especialmente na proporção de 30/70.

System of Intein-mediated PHB Purified Human Antimicrobial Peptide LL-37 / 中国生物工程杂志

The new intein-mediated PHB purify protein system is a high expression, automatic cutting, for purification, low-cost protein purification system,it is conducive to large-scale protein purification.Choose human antibacterial peptide LL-37 as the purification objects,which is poison to prokaryotic cell.We construct intein-mediated PHB purified human antimicrobial peptide LL-37 system through genetic engineering technology and use this system to purify LL-37. The results show that this system can highly express LL-37 fusion protein and purifiy the product as same size with expectations.

Selection High-Yield PHB Depolymerase Producing Strain with UV / 微生物学通报

Conidial suspension was obtained from the Penicillium sp. DS9713a which could decompose PHB. Through screening a lot of mutants with the methods of transparent zones and flask culture, five strains were selected from starting strain treated with UV and their activity were higher than the original .The best mutant strain named DS9713a-CS01, it's enzyme activity was as 197.42% high as that of the original ,furthermore, the characters of crude enzyme were studied.

STUDY ON THE PROPERTIES OF POLY(?-HYDROXYBUTYRATE)DEPOLYMERASE / 微生物学通报

Three strains having degrading poly(?-hydroxybutyrate)(PHB) activity were isolated from activated sludge of different ecological environments and areas,named DS9701, DS9710 and DS9713.The properties of PHB depolymerase produced by DS9701, DS9710 and DS9713 were studied. All the PHB depolymerases are extracellular enzyme and are induced enzyme. The time that enzyme activities of the PHB depolymerases reach the maximum is 96 hours after inoculation. The apparent optimal temperature range for crude enzymes extract is 40℃～45℃.