Increased production of chitinase by a Paenibacillus illinoisensis isolated from Brazilian coastal soil when immobilized in alginate beads.

The accumulation of chitin waste from the seafood industry is a serious environmental problem. However, this residue can be degraded by chitinases and its subproducts, such as chitosan, economically exploited. In this study, a chitinase producer bacteria, identified as Paenibacillus illinoisensis, was isolated from the Brazilian coastal city of Terra de Areia - Rio Grande Do Sul (RS) and was immobilized within alginate beads to evaluate its chitinase production. The alginate beads containing cells presented an average size of 4 mm, 99% of immobilization efficiency and increased the enzymatic activity in 40.71% compared to the free cells. The biomass during enzymatic production increased 62.01% and the total cells leaked from the alginate beads corresponded to 6.46% after 96 h. Immobilized cells were reused in a sequential batch system and remained stable for production for up to four 96-h cycles, decreasing only 21.04% of the initial activity at the end of the fourth cycle. Therefore, the methodology used for cell immobilization resulted in adequate beads to maintain cell viability during the enzymatic production, increasing enzymatic activity, showing low cell leakage from the support and appropriate recyclable capacity.

Wound healing treatment using insulin within polymeric nanoparticles in the diabetes animal model.

The aim of this work was to prepare chitosan nanoparticles containing insulin and to evaluate its therapeutic activity during wound healing in diabetic rats. The hypothesis that guided this study was that the combination of insulin within chitosan nanoparticles could stimulate the signaling pathway for wound healing. The chitosan nanoparticles were prepared by the ionotropic gelation method presenting average size of 183.3 ± 8.32 nm, polydispersity index (PDI) 0.397 ± 0.07 and zeta potential of 33.7 ± 2.45 mV for empty chitosan nanoparticles (EC) and 245.9 ± 25.46 nm and PDI 0.463 ± 0.01, and zeta potential of 39.3 ± 4.88 mV for chitosan nanoparticles containing insulin (IC). The insulin association efficiency was 97.19% ± 2.18. These nanoparticles and free insulin (FI) were incorporated within a hydrogel (Sepigel®) for topical application in the wound of 72 diabetic rats distributed in four groups: Sepigel® (S, control), free insulin (FI), empty chitosan nanoparticles (EC), and chitosan nanoparticles containing insulin (IC). The animals in each group were reorganized into three subgroups (n = 6) to assess their clinical signs after days 3, 7, and 14 from the beginning of treatments. Intense fibroplasias were observed in the free or insulin-chitosan nanoparticles groups. In the latter, a large number of blood vessels were observed at day 7th. Our data indicated that both empty and insulin-containing chitosan nanoparticles were able to stimulate inflammatory cell proliferation, and angiogenesis, followed by wound maturation.

Production of cyclodextrin glycosyltransferase by immobilized Bacillus sp. on chitosan matrix.

The whole-cell immobilization on chitosan matrix was evaluated. Bacillus sp., as producer of CGTase, was grown in solid-state and batch cultivation using three types of starches (cassava, potato and cornstarch). Biomass growth and substrate consumption were assessed by flow cytometry and modified phenol-sulfuric acid assays, respectively. Qualitative analysis of CGTase production was determined by colorless area formation on solid culture containing phenolphthalein. Scanning electron microscopy (SEM) analysis demonstrated that bacterial cells were immobilized on chitosan matrix efficiently. Free cells reached very high numbers during batch culture while immobilized cells maintained initial inoculum concentration. The maximum enzyme activity achieved by free cells was 58.15 U ml(-1) (36 h), 47.50 U ml(-1) (36 h) and 68.36 U ml(-1) (36 h) on cassava, potato and cornstarch, respectively. CGTase activities for immobilized cells were 82.15 U ml(-1) (18 h) on cassava, 79.17 U ml(-1) (12 h) on potato and 55.37 U ml(-1) (in 6 h and max 77.75 U ml(-1) in 36 h) on cornstarch. Application of immobilization technique increased CGTase activity significantly. The immobilized cells produced CGTase with higher activity in a shorter fermentation time comparing to free cells.