Tianjin University of Science and Technology

Dandan Niu

Zhengxiang Wang

Kangming Tian

Fuping Lu

Chunli Shen

The disclosure discloses a method for producing α-calcium sulfate hemihydrate whiskers by using fermentation broth for producing lactic acid with a calcium salt method as a raw material and synchronously recovering a lactic acid monomer. The method comprises the following steps: 1) after fermentation of lactic acid is ended, heating fermentation broth; 2) stirring, and adding sulfuric acid for reaction; 3) after the reaction is ended, filtering and collecting a solid part, namely α-calcium sulfite hemihydrate whiskers, and collecting a liquid part, namely a free lactic acid solution containing the lactic acid monomer; and 4) washing and drying the obtained α-calcium sulfate hemihydrate whiskers to obtain a α-calcium sulfate hemihydrate whisker finished product, filtering and concentrating the obtained free lactic acid solution to obtain a lactic acid crude product, and refining the lactic acid crude product to obtain a high-purity lactic acid monomer. The disclosure can replace the efficient separation of lactic acid in production of lactic acid with the existing calcium salt method and high value-added transformation of a calcium sulfite byproduct, thereby significantly reducing the refining cost of lactic acid and formation of wastes and facilitating improvement of lactic acid production quality and simplification of a post-extraction process technology.

Method for producing calcium sulfate hemihydrate whiskers by using fermentation broth for producing lactic acid with calcium salt method as raw material and synchronously recovering lactic acid monomer

A method of using lactase for generating galactooligosaccharide as well as the preparation and an application of the lactase are provided. Lactase (BglD305 derived fromB2301 and BglD derived fromATCC 31382) molecules from two sources are taken as the basis for molecular evolution, so as to obtain new lactase enzyme molecules with high galactooligosaccharide synthesis efficiency and good expression performance. The high-producing strain lactase is further constructed, the lactase can be efficiently synthesized during the submerged fermentation, and the enzyme molecule is secreted into the culture medium, the high-activity enzyme preparation is directly prepared from the fermentation supernatant, and the lactase expression level can achieve 2208 U/mL. As the result, the fermentation manufacturing cost of lactase is reduced, the fermentation manufacturing process is simplified, and the quality of the lactase preparation is improved.

Special enzyme for galactooligosaccharide production as well as preparation and application thereof

Disclosed are very high optically pure D- and L-lactic acid fermentation production strains and construction methods thereof and the method for preparing very high optically pure D- and L-lactic acids using the strains, wherein the deposit number of the D-lactic acid fermentation production strain is CGMCC No. 11059, and the deposit number of the L-lactic acid fermentation production strain is CGMCC No. 11060.

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Tianjin, China

Dandan Niu