Journal of Food, Agriculture and Environment

Vol 7, Issue 2,2009
Online ISSN: 1459-0263
Print ISSN: 1459-0255

A method of in situ screening for bacteria capable of producing alginate-degrading enzyme from aquatic fields


Ryohei Ueno

Recieved Date: 2009-01-17, Accepted Date: 2009-03-28


A number of reports have described the isolation and characterization of bacteria that are capable of producing alginate lyase. These bacteria are expected to be used for preparation of alginates of low molecular weight with novel physiological and physical functions. They can also be used to produce single cell detritus from brown algal thalli for feeding of aquaculture animals. So far, the isolation of alginate-degrading microorganisms from natural environments and organisms has been carried out by enrichment cultivation supplied with both peptone and sodium alginate, followed by selection of alginate-degrading microbes on a plate containing sodium alginate as a sole source of carbon for growth. Therefore, this would reduce the time and effort to screen for the microorganisms with the aforementioned ability, if they are to be concentrated at the sites for collection of environmental samples. The purpose of the present study is to examine the effectiveness of a method intended to concentrate alginate-degrading bacteria in aquatic environments to avoid exhaustive screening in the laboratory. A test tube having nine holes in its surface was filled with 15% sodium alginate gel and immersed in the sea or brackish waters for three days, after which the retrieved gel was spread on the isolation plates which comprised nutrient agar and 1.5% sodium alginate. Subsequent analyses showed that 50% of the total bacteria which formed colonies on the isolation plates had alginate lyase activity. Of these, two bacterial strains were closely related to Cellulophaga fucicola NN015860 based on the 16S rRNA gene partial sequence data. The viscous alginate gel in the tube was assumed to have served not only as an absorbent for the floating microorganisms in aquatic environments but also as a primary carbon source for the bacteria that are capable of producing alginate-degrading enzymes. In short, the alginate gel may have concentrated the bacteria of interest at the sites where the test tubes were placed. Considering that most of the alginate-degrading bacteria described so far have been obtained from the algal thalli of the brown macro-algae, the method described here should be useful for effective isolation of alginate lyase-producing bacteria from aquatic environments during summer and autumn when most of the benthonic, macro-algal thalli disappear from coastal environments.


Bacteria, alginate lyase, in situ screening, aquatic environments

Journal: Journal of Food, Agriculture and Environment
Year: 2009
Volume: 7
Issue: 2
Category: Environment
Pages: 731-735

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