Alginase enzyme production by Bacillus circulans

Abstract

Stream and soil samples were screened for microorganisms that would use alginate from mucoid Pseudomonas aeruginosa as the sole carbon and energy source. A pure culture containing large aerobic rods was isolated. The cells were about 0.8 by 2.5 Fm in size, had lateral or peritrichous flagella, had a negative Gram stain reaction, and produced spores on sporulation medium. Purified DNA was approximately 46 mol% G+C as measured by thermal denaturation. From these and other biochemical tests, the organism was identified as Bacillus circulans. The enzyme activity that degraded alginate appeared in the culture medium. Upon gel filtration, alginase activity eluted as a single peak at a position corresponding to a protein of 40,000 daltons. Activity recovered from this one-step, partial purification showed apparent endomannuronidase specificity. Like other alginases previously reported, the enzyme appeared likely to be a lyase (or eliminase). However, no Bacillus species or other gram-positive bacteria have heretofore been reported to produce extracellular enzymes with alginase activity. Several other B. circulans strains from the American Type Culture Collection also appeared to have inducible extracellular alginase activity. * Corresponding author. B. circulans strain ATCC 4513 (neotype), ATCC 14175, ATCC 15518, and ATCC 15519 were obtained from the American Type Culture Collection, Rockville, Md. Mucoid clinical isolates of P. aeruginosa were obtaihed from Children's Hospital, Birmingham, Al. Enrichment of alginase-producing bacteria from soil. Soil and stream samples from Iowa, Montana, Wyoming, and Utah were placed into medium that contained 0.5% P. aeruginosa alginic acid (prepared from clinical strains by the method of Govan and Fyfe [15]), minimal salts (5), and 0.02% yeast extract. Cultures that showed turbidity and reduction in viscosity of the medium after shaking at room temperature for 1 week were subcultured and subsequently purified.

Polysaccharide lyases

“…As already indicated, alginases (alginate lyases) are of widespread occurrence, being found in marine gastropods, in bacteriophage, in various marine microorganisms [16,31,109,114] and in some soil Bacillus spp. [42]. Although few of these enzymes have been fully purified, they have been shown to be endo-or exo-enzymes with specificity towards /3-0mannuronosyl or a-L-guluronosyl linkages ( Table 1).…”

Role of alginate lyase in cell detachment of Pseudomonas aeruginosa

“…The role of the P. aeruginosa alginate lyase in alginate production is intriguing. Several other microbes, including Bacillus circulans and two marine Pseudomonas species, that possess such an enzyme can utilize alginate as a carbon source (19,22,38). However, it appears that P. aeruginosa 8821 and 8830 are unable to do so (unpublished results).…”

Alginate Lyase Promotes Diffusion of Aminoglycosides through the Extracellular Polysaccharide of MucoidPseudomonas aeruginosa

“…Alginates can be enzymatically depolymerized by lyases (eliminases) which catalyze the cleavage of the glycosidic linkages by ␤-elimination (32). Alginate lyases are produced by a wide variety of bacteria, including Bacillus circulans (19), Klebsiella pneumoniae (5), various Pseudomonas spp. (36,39), and P. aeruginosa (4,9,21,24,34).…”