Study On The Isolation, Identification And Biological Characteristics Of A New Strain Of Sporocytophaga

Sporocytophaga is a kind of gliding bacterium that can decompose the cellulose. This bacteria is an important moiety in the cellulolytic microorganisms. But much less information is available on the cellulose biodegradation by aerobic bacteria. It is valuable for us to understand and study the cellulolytic mechanism of these cellulolytic aerobic bacteria . These works will help us to develop the cellulose resource in the nature. In this paper using filter-paper plate and CF-11 solid plate, we isolated an aerobic cellulolytic bacterium from the corn soil. The taxonomic position, life circle, cellulose-degraded characteristics and ex-polysaccharides of this bacterium was investigated in this paper.The main results obtained from this work are as follows.1. A novel aerobic cellulose-degrading bacterium has recently been isolated from cornsoil, and designated as strain JL-01. Strain JL-01 can grow by using the filter paper or ball milled cellulose CF-11 as sole carbon source. Concomitant with the cellulose degrading there was a great deal of expolysaccharides produced. The taxonomic position of strain JL-01 was investigated on the morphologic and biochemical properties. It was identified a new strain of Sporocytophaga and named Sporocytophaga sp. JL-01.2. JL-01 was observed by the scanning electron microscope after cultured on the FP liquid medium. The results shown the different Morphologic characteristics of sporocytophaga JL-01. On this basis a new possible life circle was brought forward.3. For understanding and studying the cellulolytic mechanism of Sporocytophaga sp. JL-01, the process about degradation of filter paper fibre was studied using scan electronmicroscopy. The morphological changes that Sporocytophaga sp. Jl-01 grew on filter paper were observed. The studyrevealed the JL-01 adhered tightly to the surface of filter paper fibre or penetrated into interior of the fibre through its 2.5um -5.0um bacilliform cells in the process of degrading. The bacilliform cells degrade the cellulose strongly and produced a mass of sticky polysaccharides. At the anaphase of cultured, the bacteria existed as a cycloidal dormancy body-sporocyst.4. We determined the CMCase activity and the FP-enzyme activity about the supernatant, capsule, sonicated broken cell, and the intact cell of Sporocytophaga sp. JL-01. According to these results, we make the cellulase localization of Sporocytophaga sp. JL-01. The result showed that Sporocytophaga sp. JL-01 have a extracellular CMCase, and its FP-enzyme is at the cell membrane.5. One CMCase active component was purified by gel Sephadex G-100 from the culture filtrate of strain Sporocytophaga sp. JL-01. The range of optimal temperatures and optimal pH of this CMCase for hydrolysis of CMC was 50 and pH 5.0. Data from the SDS-Gel electrophoresis indicated the molecular weight of this CMCase is 82,000. The Zn2+ have a obvious inhibit effect and Fe2+ have a weak increase effect to this CMCase activity. The analysis of CD spectrum showed that the pleated sheet structure of this CMCase was the main conformation with CMCase activity. The analysis of fluorescence spectrum showed that the tryptophan may be at the active siteof this CMCase.6. The conditions for producing exopolysaccharides of JL01 were studied. The results showed that the optimum of nitrogen resource, pH and temperature were Yeast extract powder, pH7.5, and 35, respectively. The research of degrading corn stalk and corn cortex by Sporocytophaga sp. JL01 suggested this strain had a weak degradation ability to these natural cellulose.The capsular polysaccharide of Sporocytophaga sp. JL01 was isolated by SephadexG-75. The molecular weight and constitute were determined. The molecular weight of this capsular polysaccharide is 65,000. The capsular polysaccharide was made by galactose, glucose, glucuronic acid and Mannan.The result of IR show that capsular polysaccharide is a mixed alinkage and linkage with more methyl group than other polysaccharide.