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Butyl acrylate was used as reaction terminator to control the molecular structure of hyperbranched poly(ester-amine)s (HPEA) synthesized from piperazine and trimethylolpropanetriacrylate (TMPTA). Self-assembled films were formed from HPEA as polycation and poly(sodium-p-styrenesulfonate) (PSS) as polyanion by layer-by-layer (LBL) dipping. The influence of solution pH of HPEA on aggregation behaviors of the molecules in solution, self-assembling performances, surface morphologies and hydrophility of the films were investigated. The surface morphologies could be controlled by the amphiphilic balance of HPEA in water, which was regulated by the pH.

Hyperbranched poly(ester amine) (HPEA) with terminal secondary amine groups was synthesized by the Michael addition reaction between piperazine and trimethylolpropanetriacrylate with a molar ratio of 13:6. It was further reacted with a series of aliphatic acid chlorides, including stearoyl chloride, dodecanoyl chloride, and octanoyl chloride, to yield three modified amphiphilic hyperbranched polymers, which were termed HPEA-C18, HPEA-C12, and HPEA-C8, respectively. These polymers were characterized with Fourier transform infrared, 1H NMR, gel permeation chromatography, and differential scanning calorimetry measurements. Because of the existence of interior tertiary amine groups, the modified amphiphilic polymers were used as host molecules to extract the guest acid dye, methyl orange (MO), from the aqueous layer to the organic layer on the basis of the acid–base interaction. The influences of the pH of the aqueous layer and the length of the alkyl chains in the modified polymers on the phase-transfer performances were investigated. The results indicated that more MO molecules could be extracted at a lower pH because of the formation of more quaternary ammonium ions within the host molecules. As the length of the alkyl chains in the modified polymers increased, both the transfer capability and the intermolecular aggregation at the interface were enhanced. The extracted MO could be reversibly released from the organic layer to the aqueous layer under basic conditions. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2921–2930, 2005

Anisic acid, the precursor of a variety of food flavors and industrial raw materials, can be bioconversed from anethole which extracted from star anise fruits. WGB31 strain with anisic acid molar production rate of 10.25% was isolated and identified as Burkholderia sp. Three significant influential factors, namely, glucose concentration, initial pH value, and medium volume were selected and their effects were evaluated by Box-Behnken Design (BBD). Regression analysis was performed to determine response surface methodology and the significance was tested to obtain the process model of optimal conditions for producing anisic acid. The fermentation conditions at the stable point of the model were obtained: glucose 6 g L(-1) , pH 6.2, culture medium volume 61 mL in a triangular flask with 250 ml volume. Verification test indicated that the production rate of anisic acid was 30.7%, which was three times of that before optimizing. The results provide a basis and reference for producing anisic acid by microbial transformation.

Bioleaching of Cu and Fe in low-grade chalcopyrite using Penicillium janthinellum strian GXCR was studied. As a result, shaking bioleaching was more efficient than submerged bioleaching; Cu bioleaching was much better than Fe bioleaching; under conditions of optimum carbon source (10% sucrose, W/V), optimum nitrogen source (1.5% NaNO3, W/V), shaking bioleaching and the optimum combination of conditions (initial pH 6.0 in leaching media, 5% (W/V) 200-mesh ore and initial inocula of 3.0x10(5) conidia/mL), Cu bioleaching efficiency reached 87.31% (W/W). One of the most important factors affecting Cu bioleaching in shaking bioleaching was the initial pH in leaching media (FF0.05). The major organic acids for Cu and Fe bioleaching were citric and oxalic acids, respectively. Low bioleaching efficiency by submerged bioleaching was due to low production of citric and oxalic acids. The mechanisms employed by the GXCR in Cu bioleaching included biochemical functions of citric and oxalic acids as well as ore crack caused by mechanical power generated from mycelial growth.