Improved Exopolymer Production by Chromohalobacter canadensis Cultures for Its Potential Cosmeceutical Applications


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Radchenkova N., Haskoylu M. E. , Vassilev S., Yildiz S. Y. , Boyadzhieva I., TOKSOY ÖNER E., ...More

MICROORGANISMS, vol.8, no.12, 2020 (Peer-Reviewed Journal) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 8 Issue: 12
  • Publication Date: 2020
  • Doi Number: 10.3390/microorganisms8121935
  • Journal Name: MICROORGANISMS
  • Journal Indexes: Science Citation Index Expanded, Scopus, Agricultural & Environmental Science Database, BIOSIS, CAB Abstracts, Veterinary Science Database, Directory of Open Access Journals
  • Keywords: halophilic bacterium, exopolymer, continuous cultivation, dilution rate, biocompatibility, INDUSTRIAL, ACID

Abstract

Several exopolymers with different chemical composition and correspondingly variety in their physico-chemical properties from halophilic microorganisms have still been described, however, with a low production yield. Chromohalobacter canadensis 28 isolated from Pomorie saltern synthesized an unusual exopolymer (EP) containing 72% gamma-polyglutamic acid (PGA), an essential cosmeceutical additive. Current work suggests a novel approach for effective EP synthesis by C. canadensis 28 using continuous cultures. Highest production was observed at low dilution rates reaching a level of 2.1 mg/mL at D = 0.035, similar to those in batch cultures (2.34 mg/mL), however avoiding all disadvantages of discontinuous fermentation processes. At steady state, the total quantities of the synthesized EP after 48 h cultivation for the given equipment volume in D = 0.035 h(-1) and D = 0.075 h(-1) were 8.67 and 12 g, correspondingly, while it was 2.9 g for batch culture. Process parameters did not change after a ten-day run at D = 0.35 h(-1). A degree of purity of EP fraction received from continuous cultures was significantly increased up to 93-96%. A lack of cytotoxicity and high cell viability were observed for human dermal fibroblast cells after 24 h incubation with crude EP from C. canadensis 28 and purified PGA fraction that could suggest its high potential for cosmetic applications.