Novel bacillus sp. wl-1 strain producing mannanase

#The present invention relates to a novel Bacillus sp. WL-1 strain producing mannanase, which is highly active in the neutral and the acidic media. More specifically, the present invention relates to a method for producing in large scale mannanase which is highly active in the neutral and acidic media and thus useful as a feed additive for monogastric animals, in which method the novel Bacillus sp. WL-1 strain is isolated from the soil, identified and cultured.

#Mannanase is a promising enzyme for decomposing a mannan component that constitutes hemicellulose. Hemicellulose is a constituent component of the plant cell wall containing cellulose associated with lignin and a polysaccharide most abundant in the nature next to cellulose. Hemicellulose includes mannan materials such as galactomannan and arabitogalactan contained in the seed of leguminous plants, or glucomannan and galactogluromannan of coniferous trees. The most important availability of mannanase that is included in hemicellulase together with xylanase and glucanase is saccharifying hemicellulose, which is a recyclable plant resource in the earth, into a carbon source available to organisms. But, this use of mannanase is not put into practice yet. Presently, hemicellulase is useful in industrial applications including food processing of coffee, cocoa, tea, cereal, etc. and manufacture of pulp.

#When processed with hemicellulase, grains that contain hemicellulose used for foods or feeds are converted to a form adequate for foods or feeds with an improved energy yield and a deterioration of viscidity. With an increase in the energy content of foods or feeds, it is advantageous, especially for feeds, to reduce the cost for breeding of domestic animals.

#Further objects and advantages of the invention can be more fully understood from the following detailed description taken in conjunction with the accompanying drawing in which:

#FIG. 1 is a graph showing the activity of mannanase produced by a Bacillus sp. WL-1 strain depending on the temperature and acidity (pH); and

#FIG. 2 is a graph showing the number of colonies and the activity of mannanase in a culture medium depending on the culture time when the Bacillus sp. WL-1 strain is cultured in an LB medium containing no additional carbon source and an LB medium containing 1% wheat bran and 1% galactose.

#The present invention comprises the steps of: culturing a soil sample in an LB agar medium containing an acacia fruit resin and selecting strains with a fruit resin digestion ring formed around colonies to obtain mannanase-producing microorganisms, which strains are designated as “Bacillus sp. WL-1 strain”; determining the optimum growth temperature of the Bacillus sp. WL-1 strain and examining the morphological and physiological characteristics of the Bacillus sp. WL-1 strain according to the Bergy's manuals of determinative bacteriology; determining the optimum active temperature and pH of mannanase that is an enzyme produced by the Bacillus sp. WL-1 strain; examining the effect of the individual carbon sources on the production yield of mannanase when the Bacillus sp. WL-1 strain is cultured in media that are different in the content of carbon sources, i.e., galactose and wheat bran; periodically measuring the number of colonies and the activity of mannanase while culturing the Bacillus sp. WL-1 strain in a medium containing galactose and wheat bran as carbon sources and a medium containing no carbon source, to determine the relationship between the production yield of mannanase and the number of colonies; and treating a soybean meal with the mannanase produced by the Bacillus sp. WL-1 strain and measuring the increment of a reducing sugar resulting from the digestion of mannan in the soybean meal, thereby examining the availability of the mannanase produced by the Bacillus sp. WL-1 strain as an animal feed additive.

#The LB agar medium used in the present invention contains, per 1 L of the medium, 10 g of trypton, 5 g of a yeast extract, 5 g of NaCl and 18 g of bactoagar.

#Hereinafter, the present invention will be described by way of the following examples, which are not limit the scope of the present invention.