Method for preparing bran starter for citric acid by liquid inoculation

Abstract

The invention relates to a method for preparing bran starter for citric acid by liquid inoculation, which comprises the steps of (1) inoculating the Aspergillus niger on a PDA slant culture medium for activating, culturing for 5 to 7 days at 35 to 37 DEG C to obtain Aspergillus niger slant strain; (2) inoculating the Aspergillus niger slant strain cultured in step (1) on a liquid seed culture medium, culturing for 24 to 48 hours at 35-38 DEG C and a speed of 150-300 rpm / min to obtain the Aspergillus niger liquid seed; (3) inoculating the Aspergillus niger liquid seed cultured in step (2) on a bran starter liquid medium, the inoculation amount is 0.3-2wt%, turning over at 36 to 38 DEG C and culturing for 4 to 6 days to obtain a bran starter; (4) transferring the bran starter obtained in step (3) into a fermentation tank and culturing. The progressively amplified tedious processes in citric acid fermentation process can be omitted such that the fermentation cycle is shortened, the labor costs and equipment costs are saved, the problem of microbiological contamination in the inoculation of bran in shake flask is reduced, and the fermentation process of citric acid is further optimized, thereby promoting the production of citric acid. The yield of citric acid can be improved by 5 to 10%.

Description

technical field [0001] The invention belongs to the technical field of industrial production of citric acid, in particular to a method for preparing citric acid gluten koji by liquid inoculation. Background technique [0002] Citric acid is a very important organic acid, which is widely used in food industry, pharmaceuticals, daily chemical industry and other industrial sectors. In recent years, the world's total output of citric acid has risen sharply. my country's citric acid output has reached more than 800,000 tons, exported more than 600,000 tons, and earned more than 500 million US dollars from exports. Its output and export volume rank first in the world, and it has become the world's largest of Citric Acid producing and exporting countries. At present, Aspergillus niger uses sugar fermentation to produce citric acid is an important biosynthetic pathway. Excellent strains play a decisive role in citric acid fermentation. China's citric acid fermentation has reached a...

AI Technical Summary

Problems solved by technology

Excellent strains play a decisive role in citric acid fermentation. China's citric acid fermentation has reached a very high level, but the main problem is: the traditional process is still used in the production of Aspergillus niger bran koji in my country's citric acid industry, that is, a batch of The fermented seeds need to prepare a lot of triangular flask bran koji, and then step by step amplification of the first-level seeds and second-level seeds, and finally enter the fermenter for fermentation

The bran koji of the triangular bottle is directly inoculated on the slope, the preparation process is labor-intensive, and spot checks are required before inoculation to test its fermentation ability, the process is cumbersome, and standardized production cannot be formed

Moreover, the probability of bran koji infection is high, and problems such as standardized production cannot be formed