Physiological and Biochemical Characteristics, and Biotechnological Potential of Hydrolitic Haloalkalitolerant Bacteria of Soda Sludge Storage

Abstract

Peculiarities of manifestation of hydrolytic activity of haloalkalitolerant bacteria Pseudomonas peli 3-T, Microbacterium kitamiense 16-DB, and Bacillus aequororis 5-DB, isolated from the soil of the territory of the soda sludge storage and the soda sludge of the functioning sludge reservoir of Berezniki Soda Plant (Perm Territory, Russia) were studied. It was shown that the maximum activity of extracellular lipases and amylases of the three studied bacteria were manifested at pH 11 and a high concentration of sodium chloride (50–200 g/L). Cultivation of P. peli 3-T on a mineral medium with 0.5% glycerol (source of carbon) and 0.03% urea (source of nitrogen) makes it possible to obtain biomass (6.9 g/L) and activity of extracellular lipase (1.26 U/L) and lipase associated with cells (3.02 U/mg dry cells) with a high economic ratio of substrate consumption (138%). The efficiency of immobilization of P. peli 3-T and B. aequororis 5-DB cells for use in lipid and starch biotransformation was shown. P. peli 3-T cells immobilized by adsorption on kaolin and incorporated into the structure of barium alginate and agarose gels retained from 40.4 to 63.8% of the cell lipase activity in suspension. B. aequororis 5-DB cells immobilized by adsorption on kaolin retained 42.5% of lipase and 90.7% of amylase activity as compared to the initial ones. At the same time, the activities of the P. peli 3-T and B. aequororis 5-DB enzymes were preserved during 6 consecutive reactions. The amylase activity of immobilized M. kitamiense 16-DB cells by adsorption on kaolin and chitosan decreased to 2.7–3.5% of the initial value and was completely inhibited upon immobilization by cell’s entrapment into barium alginate gels or agarose gels.