Yasar Yildiz S, Anzelmo G, Ozer T, Radchenkova N, Genc S, Di Donato P, Nicolaus B, Toksoy Oner E, Kambourova M
Department of Bioengineering, Marmara University, Istanbul, Turkey.
Istituto di Chimica Biomolecolare (ICB), CNR, Napoli, Italy.
J Appl Microbiol. 2014 Feb;116(2):314-24. doi: 10.1111/jam.12362. Epub 2013 Oct 30.
This study aims to identify a high level exopolysaccharide (EPS) producer thermophile that in turn could be used as a model organism to study the biological mechanisms and whole genome organization of EPS-producing thermophilic bacteria.
Thermophilic isolates were screened, and then growth and EPS production of the best producer Brevibacillus thermoruber strain 423 were investigated under different carbon and nitrogen sources, temperature, pH and agitation rates. Rheological characterization revealed that the EPS behaved like a typical Newtonian fluid and viscosity of the EPS solution increased with increasing Ca(2+) ion concentration. Chemical characterization by TLC, GC-MS, FT-IR and NMR suggested a heteropolymer structure with glucose as major monomer unit. High biocompatibility of pure EPS fractions suggested their potential use in biomedical applications.
This study reports on the comprehensive description of microbial production conditions as well as chemical, rheological and biological characterization of the EPS produced by B. thermoruber strain 423. The bioreactor cultures were found to reach two times higher yields and three times higher productivities when compared with literature.
Brevibacillus thermoruber strain 423 combined the advantages of its nonpathogenicity with the advantages of fast productivity and hence proved to be a very promising model organism and cell factory for microbial EPS production.
本研究旨在鉴定一种高产胞外多糖（EPS）的嗜热菌，该嗜热菌可作为模式生物，用于研究产EPS嗜热菌的生物学机制和全基因组组织。
对嗜热菌株进行筛选，然后研究最佳生产者嗜热栖热短芽孢杆菌菌株423在不同碳源、氮源、温度、pH值和搅拌速率下的生长及EPS产量。流变学特性表明，该EPS表现为典型的牛顿流体，且EPS溶液的粘度随Ca(2+)离子浓度的增加而升高。通过薄层层析、气相色谱 - 质谱联用仪、傅里叶变换红外光谱和核磁共振进行的化学特性分析表明，其具有以葡萄糖为主要单体单元的杂聚物结构。纯EPS组分的高生物相容性表明其在生物医学应用中的潜在用途。
本研究全面描述了嗜热栖热短芽孢杆菌菌株423产生的EPS的微生物生产条件以及化学、流变学和生物学特性。与文献相比，发现该生物反应器培养物的产量提高了两倍，生产率提高了三倍。
嗜热栖热短芽孢杆菌菌株423兼具无致病性的优点以及快速生产的优势，因此被证明是用于微生物EPS生产的非常有前景的模式生物和细胞工厂。
