Iranian Journal of Chemical Engineering (IJChE)

Abstract Conventional plastics have been a significant source of the environmental pollution, prompting considerable research into the development of biodegradable plastics using biological methods. Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) has garnered particular attention due to its unique properties, including high flexibility and resistance to organic solvents. It has been demonstrated that certain microorganisms possess the intracellular capability to synthesize this biopolymer from organic waste. This study investigates bacteria that have been isolated from the municipal landfill of the Kermanshah Waste Recycling and Organic Fertilizer Production Company. Among the isolates, a strain capable of synthesizing biopolymers, exhibiting high similarity to the genus Stenotrophomonas geniculata strain Flmat 1, was identified via 16S rRNA gene sequencing. In order to verify the production of the biopolymer, Fourier-transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1H-NMR) analyses were employed. The results have shown that the isolated bacteria is capable of producing PHBV from unrelated carbon sources from waste food and producing 2.835 g/L biopolymer with the yield of 0.52 g PHBV per gram of CDW using waste food, at the pH of 9, temperature of 33°C, concentrations of 13.25 g/L and 27.71 g/L of nitrogen and glucose respectively.

Abstract Guanidine hydrochloride has been widely used in the initial recovery steps of active protein from the inclusion bodies in aqueous two-phase system (ATPS). The knowledge of the guanidine hydrochloride effects on the liquid-liquid equilibrium (LLE) phase diagram behavior is still inadequate and no comprehensive theory exists for the prediction of the experimental trends. Therefore the effect the guanidine hydrochloride on the phase behavior of PEG4000+ potassium phosphate+ water system at different guanidine hydrochloride concentrations and pH was investigated in this study. To fill the theoretical gaps, the typical of support vector machines was applied to the k-nearest neighbor method in order to develop a regression model to predict the LLE equilibrium of guanidine hydrochloride in the above mentioned system. Its advantage is its simplicity and good performance, with the disadvantage of an increase the execution time. The results of our method are quite promising: they were clearly better than those obtained by well-established methods such as Support Vector Machines, k-Nearest Neighbour and Random Forest. It is shown that the obtained results are more adequate than those provided by other common machine learning algorithms.

Abstract The partition coefficient of guanidine hydrochloride for the PEG4000+ Phosphate +Water system is presented at 298.15 K. The partition coefficient of guanidine hydrochloride was near unity. It was shown that partition coefficient of guanidine
hydrochloride was dependent on the concentration of guanidine hydrochloride, pH and PEG/phase forming salt (%w/w) ratio. In most systems the partitioning coefficient of Guanidine is more than one, which means guanidine preferred polymer-rich phase.