The present invention relates to a synthetic promoter capable of controlling the expression of a target gene at various locations in the genome of an acid-resistant strain, and more particularly to a synthetic promoter including a core promoter derived from an acid-resistant strain and an upstream activating sequence (UAS) element serving as an enhancer. When the present invention is applied to a variety of genetic and metabolic engineering techniques for acid-resistant yeast, various metabolic networks can be configured as desired while controlling the expression level of the target gene, so a method of producing various metabolites using acid-resistant yeast is provided, and the cost of producing the metabolites can be greatly reduced depending on the properties of the acid-resistant yeast.

A method for enzymatically preparing a n-3 polyunsaturated fatty acid diacylglycerol using oil rich in n-3 polyunsaturated fatty acid as raw material to prepare diacylglycerol oil with selective enzymatic hydrolysis. Before the enzymatic reaction, the raw materials are homogenized to improve the catalytic efficiency of lipase in the hydrolysis and achieve the purpose of reducing the reaction time and the addition amount of lipase. As a result, the cost of industrial diacylglycerol preparation is reduced, ultimately reducing the cost of industrial diacylglycerol preparation. Therefore, the present invention provides an effective, mild and low-cost enzymatic method for preparing diacylglycerol rich in n-3 polyunsaturated fatty acids, which has a promising potential for industrial application.

A preparation method of an ionic rare earth leaching agent includes the following steps: (1) domestication microorganisms with rare earth activated mineral powder culture medium to obtain a microbial suspension; (2) amplifying and culturing the microbial suspension and additives to obtain the amplified culture medium; and (3) mixing the modified sesbania gum with the amplified culture medium to obtain the ionic rare earth leaching agent. The activated mineral powder is the active metal-containing mineral powder in nature, which has excellent cation exchange function after activation, and the activated mineral powder and ionic rare earth mineral powder are used as the medium components to domesticate microorganisms, so that microorganisms can survive in the above-mentioned ionic solution and improve the leaching rate of synergistic leaching ionic rare earth.