Abstract:

The aim of this experiment is to screen cellulose degrading bacteria and explore their feasibility for fermentation of abandoned stems and leaves of Brassica oleracea. Using broccoli planting soil and laboratory preserved bacterial strains as screening sources, the carboxymethyl cellulase (CMC) Congo red staining method was used for initial screening. CMC activity and filter paper enzyme activity (FPA) were used as indicators for re screening, and a high cellulase producing strain, XLG2-1, was obtained. Through 16S rRNA gene sequence analysis and morphological and physiological and biochemical analysis, it was determined as Bacillus pumilus. Inoculate the strain into abandoned stems and leaves of Brassica oleracea for fermentation, and it was found that the content of crude protein, small peptides, and crude polysaccharides increased by 0.41, 11.5 and 10.4 percentage points respectively compared with that before fermentation. The content of crude fat, crude fiber, and crude ash decreased by 0.21, 0.25 and 0.02 percentage points respectively compared with that before fermentation. The scanning electron microscope results showed that the sample structure after fermentation was loose, with a large number of pores on the surface and bacterial attachment, indicating that the bacteria can decompose and utilize the abandoned stems and leaves of of Brassica oleracea, which helps to solve the problem of its resource utilization.

Key words: cellulose, Bacillus pumilus, abandoned stems and leaves of Brassica oleracea, fermentation