Affiliations 

  • 1 Chemistry of Natural and Microbial Products Department, National Research Centre, Dokki 12622, Giza, Egypt
  • 2 Institute of Bioproduct Developments (IBD), Universiti Teknologi Malaysia (UTM), 81310 Johor Bahru, Johor, Malaysia
  • 3 Botany and Microbiology Department, Faculty of Science, Al-Azhar University, Nasr City, Cairo, Egypt
  • 4 Cancer Biology and Genetics Laboratory, Centre of Excellence for Advanced Sciences, National Research Centre, Dokki 12622, Cairo, Egypt; Biochemistry Department, National Research Centre, Dokki 12622, Cairo, Egypt; Clinical Laboratory Department, College of Applied Medical Sciences, Taif University, Al Mutamarat Rd, Al Mathnah, At Taif 26521, Saudi Arabia
  • 5 Chemistry of Natural and Microbial Products Department, National Research Centre, Dokki 12622, Giza, Egypt. Electronic address: mona_esawy@hotmail.com
J Biosci Bioeng, 2019 Jun;127(6):655-662.
PMID: 30795878 DOI: 10.1016/j.jbiosc.2018.09.008

Abstract

This study focused on kinetics of levan yield by Bacillus subtilis M, in a 150 L stirred tank bioreactor under controlled pH conditions. The optimized production medium was composed of (g/L): commercial sucrose 100.0, yeast extract 2.0, K2HPO4 3.0 and MgSO4⋅7H2O 0.2; an increase in both carbohydrates consumption and cell growth depended on increasing the size of the stirred tank bioreactor from 16 L to 150 L. The highest levansucrase production (63.4 U/mL) and levan yield of 47 g/L was obtained after 24 h. Also, the specific levan yield (Yp/x) which reflects the cell productivity increased with the size increase of the stirred tank bioreactor and reached its maximum value of about 29.4 g/g cells. These results suggested that B. subtilis M could play an important role in levan yield on a large scale in the future. Chemical modifications of B. subtilis M crude levan (CL) into sulfated (SL), phosphorylated (PL), and carboxymethylated levans (CML) were done. The difference in CL structure and its derivatives was detected by FT-IR transmission spectrum. The cytotoxicity of CL and its derivatives were evaluated by HepGII, Mcf-7 and CaCo-2. In general most tested levans forms had no significant cytotoxicity effect. In fact, the carboxymethylated and phosphrylated forms had a lower anti-cancer effect than CL. On the other hand, SL had the highest cytotoxicity showing SL had a significant anti-cancer effect. The results of cytotoxicity and cell viability were statistically analyzed using three-way ANOVA.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.