Degradation Of Corn Gluten Meal And Preliminary Study Of Corn Small Molecular Peptide

Corn gluten meal is a rich protein resource,which can be used to develop a variety of amino acids,small peptides,feeds,culture media and other derived products.In this paper,corn gluten meal is used as the sole carbon and nitrogen source to design a screening medium for corn gluten meal and screen corn gluten meal degrading bacteria,so as to further study and develop corn gluten meal extension products.The results are as follows:1.Corn gluten meal screening medium was designed with corn gluten meal as the sole carbon source and nitrogen source.More than 300 corn gluten meal degrading bacteria were screened.After shake flask fermentation and re-screening,strain L289 with good degradation effect was obtained.The free amino acid content in liquid fermentation of this strain was up to 1438.80?g/mL.Through morphological identification and ITS sequence analysis,the strain belongs to the genus Aspergillus Niger,therefore,the strain is named Aspergillus Niger L289.2.Taking Aspergillus Niger L289 as corn gluten meal degrading bacteria,through single factor and orthogonal test liquid fermentation determination analysis,the most suitable medium formula of Aspergillus niger L289 is:corn gluten meal 4.0%,CaCl ₂0.05%,initial pH 7.0;The optimal fermentation conditions were as follows:fermentation temperature 34?,shaking table rotation speed 150 rpm,fermentation time 4 d,hydrolysis of corn gluten meal in 250 mL triangular flask with 60 mL liquid volume,without adding any carbon source.Under these conditions,the free amino acid was 2407.63?g/mL.3.Comparing and analyzing the products of corn protein powder hydrolyzed by acid protease,neutral protease and alkaline protease and the corn protein powder fermented and degraded by Aspergillus Niger L289 on the market,the products have common free amino acids identified by thin layer color chromatography,namely leucine,valine,glutamic acid and alanine,of which glutamic acid is the largest,valine is the second,alanine is the third and valine is the fourth;At the same time,there are obvious trailing spots suspected to be small molecular peptides.The difference is that the decomposition product of Aspergillus Niger L289 has lighter spot color and less free amino acid content at Rf value of 0.33-0.66.Some spots with Rf value of 0-0.33 are very dark and are suspected to be small molecular peptides,which is the prominent feature of Aspergillus Niger L289 fermentation products.4.Hydrolyzing with hydrochloric acid to analyze the major suspected small molecular peptides of Aspergillus Niger L289,and qualitative analysis with thin layer chromatography showed that the amino acid groups of the small peptides were phenylalanine,valine and glutamic acid.