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β-galactosidase, as a safe and nontoxic enzyme preparation, has been not only widely used in food industry and medical fields, but also has great application potential in biotechnology fields, such as enzyme engineering and protein engineering. Microbial fermentation, as a mainstream production method of β-galactosidase, still has some problems including long fermentation time and low extraction rate. While using the heterologous expression system of engineering bacteria to produce β-galactosidase shows the advantages of high expression quantity and low cost. This paper focuses on the gene source, expression host bacteria, expression methods of β-galactosidase heterologous expression system and its application value, to be aimed at providing scientific basis and theoretical reference for the development and utilization of novel β-galactosidase products.

Water changing conditions of a lake will affect the physical and hydrological conditions and ecology of the lake and groundwater. The unique "river-lake phase" transition of the Poyang Lake complicates the surface water-groundwater exchange process in the area. Therefore, this study uses Visual MODFLOW to build a 3D numerical model of groundwater transient flow and uses the LAK3 module to realize the dynamic simulation of the lake water area by inputting the runoff from five rivers into the lake and the Poyang Lake into the Yangtze River. The RMSE between the simulated and measured values of lake water level is 0.225 m, and between the simulated and measured values of groundwater level is 0.571 m. The month-on-month ratio variation of the Poyang Lake area simulated by the model ranges from −41% to 83%, consistent with the remote sensing images. This model reduces the constraint of lakes as boundary conditions, can effectively depict the frequently-changing water level and lake area, and accurately simulate the response of groundwater flow field and surface water-groundwater interaction relationship to the height dynamics of lake water. During the dry season, the lake is mainly recharged by groundwater, with an exchange flux ranging from 2.03×107 to 10.58×107 m3/mon. During the wet season, the lake water discharges into groundwater with an exchange flux ranging from 2.04×107 to 16.53×107 m3/mon, with the average groundwater level rise in the lake region and surrounding areas by 2~3 m compared to the dry season. The groundwater flows from the lake region to the surrounding areas. This study contributes an effective numerical simulation method for areas with dramatic changes in surface water bodies. The results can provide a basis for future water resources management and environmental assessment in the Poyang Lake Plain.

Enzyme catalyzed plastein reactions refer to the process of catalyzing concentrated protein hydrolysate into protein analogues by protease under suitable conditions. Enzyme catalyzed plastein reactions can not only make up for the defects of natural protein in the amino acid composition, improve protein functionality and the flavor of protein hydrolysates, and provide new protein sources for scientific research and production, but also the products obtained by this method have high bioavailability, and no side effects, so it has received extensive attention from the scientific community and has been gradually applied to the food industry. This article introduces the mechanism, influencing factors, product characteristics and applications of enzyme catalyzed plastein reactions in the food field, in order to provide new methods for the improvement of food quality and new ways for the development of new foods.

Corn gluten meal is a major by-product of corn wet-milling process in the starch industry. The low water solubility and deficiency of essential amino acids of corn gluten meal limits its application in the food industry, while corn polypeptides after enzymatic hydrolysis can greatly improve its functions and biological activities, it is one of the high value-added utilization methods. This review encompasses the studies reported to date on the main preparation methods of corn polypeptides, and also describes its bioactivities including antioxidant, antiglycemia, antihypertensive, hepatoprotective, pointing out the existing problems and future development prospects. The paper is of great significance for food enterprises to utilize corn gluten meal efficiently to develop bioactive peptides and improve economic benefits of the industry.