Method for producing lactic acid by using sugar liquor fermentation

Abstract

The invention relates to a method for producing lactic acid by using sugar liquor fermentation, which comprises the following steps of: (1) preparing raw materials, namely adding sugar liquor, corn pulp solution and yeast extract into a fermentation tank in a volume ratio of 100: 0.015-0.025: 0.004-0.013; (2) heating and sterilizing the raw materials; (3) adjusting the pH of the solution to be between 5.4 and 5.6; and (4) adding lactic acid bacteria into the solution to perform fermentation, namely cooling the solution obtained in the step (3) to between 48 and 50 DEG C, adding the lactic acid bacteria in a volume which is 10 to 15 percent of the total volume of the solution in the fermentation tank, keeping the temperature in the fermentation tank between 48 and 50 DEG C, continuously introducing sterile air into the fermentation tank in a flow of 0.75 to 4m<3> / h in every ton of solution, keeping the pressure in the fermentation tank between 0.4 and 0.8MPa, stirring the solution, adding saturated solution of Ca(OH)2 into the solution to keep the pH of the solution between 6.0 and 6.2, and detecting the glucose content of the solution, wherein when the glucose content is 0, the fermentation is finished. The method of the invention reduces the fermentation period, and improves the fermentation efficiency; and after the fermentation is finished, the solution contains low residual total sugar and residual reducing sugar and high produced acid.

Description

technical field [0001] The invention relates to lactic acid and its fermentation process, in particular to a method for producing lactic acid by fermenting high-concentration sugar clear liquid. Background technique [0002] Lactic acid is an organic acid obtained from agricultural and sideline products through microbial fermentation and extraction. It is the monomer raw material of polylactic acid, a degradable and environmentally friendly material. It is widely used in food, beverage, medicine, health products, chemical industry, degradable plastics and many other fields. [0003] The production of lactic acid mainly includes "chemical synthesis", "enzymatic synthesis" and "fermentation production", among which the most widely used is the production of lactic acid by fermentation. At present, in the production of lactic acid by fermentation, many enterprises have low fermentation efficiency due to immature fermentation process indicators and unreasonable control of raw ma...

AI Technical Summary

Problems solved by technology

[0004] (1) The fermentation period is long, and the fermentation period of most enterprises is about 70 hours;

[0005] (2) Acid production and acid production rate are low. Domestic large-scale production of acid production is less than 120g / L. World-scale lactic acid production can reach 130-150g / L, and acid production rate is generally 1.5-2g / L·h ;

[0007] Therefore, most lactic acid enterprises in my country cannot produce lactic acid on a large scale