Mutanase from Paenibacillus sp. MP-1 produced inductively by fungal α-1,3-glucan and its potential for the degradation of mutan and Streptococcus mutans biofilm

Laetiporus sulphureus is a source of α-1,3-glucan that can substitute for the commercially-unavailable streptococcal mutan used to induce microbial mutanases. The water-insoluble fraction of its fruiting bodies from 0.15 to 0.2% (w/v) induced mutanase activity in Paenibacillus sp. MP-1 at 0.35 μ ml−1. The mutanase extensively hydrolyzed streptococcal mutan, giving 23% of saccharification, and 83% of solubilization of glucan after 6 h. It also degraded α-1,3-polymers of biofilms, formed in vitro by Streptococcus mutans, even after only 3 min of contact

Enhancement of mutanase production in Trichoderma harzianumby mutagenesis

Conidia of TrichodermaharzianumF-340, an active producer of fungal mutanase, were mutagenized with physical and chemical mutagens used separately or in combination. After mutagenesis, the drop in conidia viability ranged from 0.004% to 71%. Among the applied mutagens, nitrosoguanidine gave the highest frequency of cultures with enhanced mutanase activity (98%). In total, 400 clones were isolated, and preliminarily evaluated for mutanase activity in flask microcultures. Eight most productive mutants were then quantified for mutanase production in shake flask cultures. The obtained results fully confirmed a great propensity of all the tested mutants to synthesize mutanase, the activity of which increased from 59 to 107% in relation to the parental T.harzianumculture. The best mutanase-overproducing mutant (T. harzianumF-340-48), obtained with nitrosoguanidine, produced the enzyme activity of 1.36 U/ml (4.5 U/mg protein) after 4 days of incubation in shake flask culture. This productivity was almost twices higher than that achieved by the initial strain F-340, and, at present, is the best reported in the literature. The potential application of mutanase in dentistry is also discussed

Optimization of conditions for the efficient production of mutan in streptococcal cultures and post-culture liquids

The strain Streptococcus sobrinus CCUG 21020 was found to produce water-insoluble and adhesive mutan. The factors influencing both stages of the mutan production, i.e. streptococcal cultures and glucan synthesis in post-culture supernatants were standardized. The application of optimized process parameters for mutan production on a larger scale made it possible to obtain approximately 2.2 g of water-insoluble glucan per 1 l of culture supernate - this productivity was higher than the best reported in the literature. It was shown that some of the tested beet sugars might be successfully utilized as substitutes for pure sucrose in the process of mutan synthesis. Nuclear magnetic resonance analyses confirmed that the insoluble biopolymer synthesized by a mixture of crude glucosyltransferases was a mixed-linkage (1?3), (1?6)-a?-D-glucan (the so-called mutan) with a greater proportion of 1,3 to 1,6 linkages