Semi-scale production of PHAs from waste frying oil by Pseudomonas fluorescens S48

The present study aimed at developing a strategy to improve the volumetric production of PHAs by Pseudomonas fluorescens S48 using waste frying oil (WFO) as the sole carbon source. For this purpose, several cultivations were set up to steadily improve nutrients supply to attain high cell density and high biopolymer productivity. The production of PHAs was examined in a 14 L bioreactor as one-stage batch, two-stage batch, and high-cell-density fed-batch cultures. The highest value of polymer content in one-stage bioreactor was obtained after 60 h (33.7%). Whereas, the two-stage batch culture increased the polymer content to 50.1% after 54 h. High-cell-density (0.64 g/L) at continuous feeding rate 0.55 mL/l/h of WFO recorded the highest polymer content after 54 h (55.34%). Semi-scale application (10 L working volume) increased the polymer content in one-stage batch, two-stage batch and high cell density fed-batch cultures by about 12.3%, 5.8% and 11.3%, respectively, as compared with that obtained in 2 L fermentation culture. Six different methods for biopolymer extraction were done to investigate their efficiency for optimum polymer recovery. The maximum efficiency of solvent recovery of PHA was attained by chloroform-hypochlorite dispersion extraction. Gas chromatography (GC) analysis of biopolymer produced by Pseudomonas fluorescens S48 indicated that it solely composed of 3-hydrobutyric acid (98.7%). A bioplastic film was prepared from the obtained PHB. The isolate studied shares the same identical sequence, which is nearly the complete 16S rRNA gene. The identity of this sequence to the closest pseudomonads strains is about 98-99%. It was probably closely related to support another meaningful parsiomony analysis and construction of a phylogenetic tree. The isolate is so close to Egyptian strain named EG 639838.

Rates and Predictors of Consistent Condom-use by People Living with HIV/AIDS on Antiretroviral Treatment in Uganda.

Antiretroviral treatment (ART) has been recognized as one of the methods for reducing the risk of HIV transmission, and access to this is being rapidly expanded. However, in a generalized HIV epidemic, ART could increase unprotected sex by people living with HIV/AIDS (PHAs). This paper assessed the rates and predictors of consistent condom-use by sexually-active PHAs after initiating ART. The study used crosssectional data on sexual behaviour of 269 sexually-active ART-experienced individuals (95 males and 174 females) aged 18 years and above. The results revealed that 65% (70% of men and 61% of women) used condom consistently after initiating ART. Consistent use of condom was more likely if PHAs had secondary- or tertiary-level education and had more than one sex partner in the 12 months preceding the study. However, PHAs were less likely to have used condom consistently if they worked in the informal and formal sectors, belonged to the medium- and high-income groups, and were married. PHAs, who were on ART for less than 1 year and 1-2 year(s), had a good self-perception of health, had a sexual partner who was HIV-negative or a partner with unknown HIV status, and desired to bear children, were also less likely to have used condom consistently. The paper concluded that, although the majority of PHAs consistently used condom, there was potential for unprotected sex by PHAs on ART.

BIOSYNTHESIS OF POLYHYDROXYALKANOATES BY RHODOCISTA PEKINGENSIS / 微生物学通报

In this article we report the results on the synthesis and accumulation of PHAs by Rhodocista pekingensis (strain 3-p), a phototroph that was isolated from wastewater treatment plant. Our results showed that the optimal conditions for PHAs accumulation with strain 3-p were as following: 0.01% Yeast Extract, 0.01% NH 4Cl, Acetate 5 g/L, and medium pH of 7.0～7.2.Under optimized conditions, strain 3-p accumulated PHAs up to 60% of its cellular dry weight. Enzymatic activities of ?-ketothiolase, acetoacetyl-CoA reductase, and PHA polymerase were detected and their activities increased as PHA synthesis initialized. Based on these study, we proposed the metabolic pathway of this strain should be:Acetate (or other fatty acids) - Acetyl-CoA --- thiolase Acetoacetyl-CoA --- reductase D (-)-?-Hydroxybutyryl-CoA ----- PHA polymerase PHAs.