Screening and identification of a lignocellulose-degrading strain and its application in highland barley fermentation

Abstract

This study aimed to screen out bacterial strains with higher lignocellulolytic degradation enzyme activity and explore the effect of this strain on the highland barely soluble dietary fiber content through fermentation. Soil samples were collected from the ground of Nanjing Agriculture University (Nanjing, China) and used for enrichment culture. The methods used to screen the bacteria with high lignocellulose-degrading ability included decolorization test of aniline blue, hydrolyzation circle measurement of sodium carboxymethyl cellulose, disintegration test of filter paper strip and detection of enzyme activity. Six bacteria were isolated with lignocellulose degrading ability, of which LM1-strain possessed high lignocellulose degrading ability. The LM1 strain was identified as Bacillus velezensis by morphological, physiological, biochemical characteristics and molecular sequence analysis. Antibiotic sensitivity tests and hemolysis tests showed that strain LM1 was sensitive to all antibiotics and caused no hemolysis, indicating the safety of strain LM1. Strain LM1 was used to ferment highland barley whole grain flour and the content of soluble dietary fiber reached high levels (12.57 g/100 g), which was 2.07 times that of the raw barley soluble dietary fiber (6.07 g/100 g). The purity of soluble dietary fiber also reached the level of enzymatic extraction. The results will enrich the types of fermentation strains and promote the development and utilization of cereals and their by-products.

Keywords

• lignocellulose degradation
• bacillus velezensis lm1
• screening
• identification
• sdf
• highland barley