Polyhydroxyalkanoate synthesis based on glycerol and implementation of the process under conditions of pilot production.

The present study addresses the synthesis and properties of polyhydroxyalkanoates (PHA) of different composition synthesized by Cupriavidus eutrophus B-10646 using glycerol as a carbon substrate. Poly(3-hydroxybutyrate) [P(3HB)] was effectively synthesized in fed-batch culture in a 30-L fermenter on glycerol of various purification degrees, with 99.5, 99.7, and 82.1% content of the main component. Purified glycerol (99.7%) was used for 150-L pilot scale fermentation. The total biomass and P(3HB) concentration reached 110 and 85.8 g/L, respectively, after 45 h of fed-batch fermentation. An average volumetric productivity of P(3HB) was 1.83 g/(L h). The degree of crystallinity and molecular weight of P(3HB) synthesized on glycerol were lower than and temperature characteristics were the same as those of P(3HB) synthesized on sugars.

Constructing sustained-release herbicide formulations based on poly-3-hydroxybutyrate and natural materials as a degradable matrix.

BACKGROUND: The purpose of the present study was to develop ecofriendly herbicide formulations. Its main aim was to develop and investigate slow-release formulations of herbicides (metribuzin, tribenuron-methyl, and fenoxaprop-P-ethyl) of different structure, solubility, and specificity, which were loaded into a degradable matrix of poly-3-hydroxybutyrate (P(3HB)) blended with available natural materials (peat, clay, and wood flour). RESULTS: Differences in the structure and physicochemical properties of the formulations were studied depending on the type of the matrix. Herbicide release and accumulation in soil were associated with the solubility of the herbicide. Fourier-transform infrared spectroscopy showed that no chemical bonds were formed between the components in the experimental formulations. Degradation of the formulations in agro-transformed soil in laboratory conditions was chiefly influenced by the shape of the specimens (granules or pellets) while the effect of the type of filler (peat, clay, or wood flour) was insignificant. The use of granules enabled more rapid accumulation of the herbicides in soil: their peak concentrations were reached after 3 weeks of incubation while the concentrations of the herbicides released from the pellets were the highest after 5-7 weeks. Loading of the herbicides into the polymer matrix composed of the slowly degraded P(3HB) and natural materials enabled both sustained function of the formulations in soil (lasting between 1.5 and ≥3 months) and stable activity of the otherwise rapidly inactivated herbicides such as tribenuron-methyl and fenoxaprop-P-ethyl. CONCLUSION: The experimental herbicide formulations enabled slow release of the active ingredients to soil. © 2019 Society of Chemical Industry.

Constructing Slow-Release Fungicide Formulations Based on Poly(3-hydroxybutyrate) and Natural Materials as a Degradable Matrix.

Slow-release fungicide formulations (azoxystrobin, epoxiconazole, and tebuconazole) shaped as pellets and granules in a matrix of biodegradable poly(3-hydroxybutyrate) and natural fillers (clay, wood flour, and peat) were constructed. Infrared spectroscopy showed no formation of chemical bonds between components in the experimental formulations. The formulations of pesticides had antifungal activity against Fusarium verticillioides in vitro. A study of biodegradation of the experimental fungicide formulations in the soil showed that the degradation process was mainly influenced by the type of formulation without significant influence of the type of filler. More active destruction of the granules led to a more rapid accumulation of fungicides in the soil. The content of fungicides present in the soil as a result of degradation of the formulations and fungicide release was determined by their solubility. Thus, all formulations are able to function in the soil for a long time, ensuring gradual and sustained delivery of fungicides.