English

M Ashour Sanaa,I Eldiwany Ahmed,A Maany Dina,M H Kheiralla Zeinab

doi:10.5897/ajmr12.953

Abstract

In screening for marine bacterial polysaccharide lytic enzymes, the most potent isolate was identified as Bacillus cereus NRC-20. This strain showed high alginase, dextrinase, pectinase and carboxymethyle-cellulase productivity when production medium was adjusted at pH 6.0 and contains (g/l): 3.0 sodium alginate, 3.0 malt extract, 30.0 jatropha cake and inoculated with 8% (v/v) of a 24 h old cell suspension and incubated at 30°C for 48 h on a rotary shaker at 200 rpm. These enzymes mixture were precipitated by 60% acetone and purified by using sephadex G-100, whereas SDS-PAGE suggested a molecular weight of approximately 17, 20, 89 and 279 KDa, respectively. The optimum partially purified enzymes activity when enzyme protein concentration was 27.4 mg/ml and substrate concentration 5.0 g/l shown after 90 min of incubation at 30°C and pH 5 and stable at 60°C for 60 min. The enzymes activities were enhanced in the presence of 0.02 M Na+ and K+ ions and completely inactivated by Mg+2, Cu+2, Co+2 and Pb+2 The enzymes mixture affected the matrix integrity of different microbial biofilms artificially grown on stainless steel sheets of Bacillus subtilis NRRL B-4219, Staphylococcus aureus ATCC 29213, Pseudomonas aeruginosa ATCC 27953 and Escherichia coli ATCC 25922. Key words: Bacillus cereus, polysaccharide lytic enzymes production, fermentation parameters, enzyme characterization, biofilm removal.

Highlights

Some local marine bacterial strains were tested for their productivity of extracellular polysaccharide lytic enzymes
Exopolysaccharides are a major component of most biofilm matrices (Orgaz et al, 2006; Fernández et al, 2012), the absence of exopolysaccharide synthesis and export, bacteria can adhere to the surfaces but unable to form multilayer biofilms and due to the heterogeneity of the extracellular polysaccharides within the biofilms, a mixture of exopolysaccharide lytic enzymes is necessary for sufficient degradation of bacterial biofilm (Xavier et al, 2005; Kaplan, 2010)
The investigated enzymes production and properties in this study are, a mixture of alginase, dextrinase, pectinase and carboxymethyl cellulase produced by marine B. cereus NRC-20, whereas some investigations reported more and more microorganisms from marine habitats that can produce polysaccharide lyric enzymes (Kaplan, 2010) and they have been attracting more attention as a resource for new enzymes, because the microbial enzymes are relatively more stable and active than the corresponding enzymes derived from plant or animal (Gupta et al, 2003; Byrd et al, 2011)