0000000000309392
AUTHOR
L Savenkova
PHA Latex Composite Films: Mechanical Properties and Surface Visualization
Homopolymer PHB and copolymer PHB/HV containing granules were isolated from Azotobacter chroococcum cells and used for latexes formation. Composite latex films were formed from the PHB and PHB/HV latexes with different content of poly (vinyl alcohol) and glycerol and a hydrophobic fluorescent benzanthrone derivated dye 3-piperidinobenzanthrone, possessed high fluorescence intensity in a system with PHA granules. Fluorescence based methods were used for characterization of the elaborated latex film by their stability at high temperature and for visualization of the film surfaces PHA granules distribution. Film stability in phosphate buffered saline was evaluated by dye migration activity in …
Effect of iron and aeration on superoxide dismutase and catalase activity of PHB-producing Azotobacter chroococcum
Abstract The effect of aeration level and iron concentration on Azotobacter chroococcum 23 growth, PHB accumulation and antioxidative enzyme activities was investigated in shake flask experiments. Biomass yield and carbon source conversation coefficients increased in the presence of iron in the growth medium and under decreased aeration. The highest biomass production was observed for the culture grown in a medium with 36 μM of initial iron concentration and moderate aeration level. The highest PHB accumulation level (70–72% from cell dry weight) under our experimental conditions was observed at decreased aeration in the growth medium with 180 μM of initial iron concentration. Results obtai…
PHB-based films as matrices for pesticides
Abstract The effects of pesticides incorporated into PHB-based polymeric matrices on the biodegradability of films and antifungal efficiency of immobilised pesticides to Botrytis cinerea was studied. The mass loss of tested PHB-based films for 2 weeks was 40–50% and after 4 weeks 92–96% of the initial mass. The fungicides Ronilan and Sumilex immobilised into the polymeric matrices did not depress the film degradation rate. PHB-based films caused changes in the soil microorganism association. Fungicides immobilised in PHB-based matrices decreased the count of the phytopathogenic fungus B. cinerea.
Changes in the Pi uptake and polyP accumulation in Saccharomyces cerevisiae strains deficient in the synthesis of trehalose and/or glycerol
Abstract The intracellular level of free inorganic orthophosphate (P i ) in yeast cells generally depends on the P i uptake capacity, energy state of the cells in respect to the activity of the membrane-associated ATPases and on the activity of metabolic pathways involved in the production of glycerol and trehalose. Batch fermentation was performed to investigate the carbon substrate consumption, the P i uptake capacity and product formation by four Saccharomyces cerevisiae strains differing in their ability to produce glycerol and/or trehalose. The consumption of P i in mutant strains with a lack of the synthesis of the trehalose and/or glycerol exceeded the level for a wild type strain ab…