Marcin Åukaszewicz
University of Wroclaw, Poland
Title: Microbial production of biopolymers using solid-state fermentation with Bacillus subtilis natto
Biography
Biography: Marcin Åukaszewicz
Abstract
Biopolymers are obtained from a wide range of microorganisms and plants. Microbial polymers are produced by the fermentation process or by chemical polymerisation of monomers. They have a wide variety of applications and can potentially replace synthetic materials. Using industrial by-products to produce exopolysaccharides can reduce the costs associated with their biosynthesis and can solve the problem of waste management after their production. It is important to select an appropriate microorganism that does not endanger human health. Solid-state fermentation (SSF) has biotechnological advantages such as higher fermentation productivity and higher product concentration. Over past five years, there have been significant developments in this method, unfortunately these advances have mainly occurred at the laboratory scale. Bacillus subtilis natto is a well-known GRAS microorganism that produces the biopolymer levan. Levan is a polymer consisting of D-fructofuranose units joined by β-(2,6) linkages and is produced by both plants and bacteria. Microbial levan potentially has a very wide range of applications in the food industry, cosmetics, pharmaceuticals, and medicine. Industrial application of levan depends on its molecular weight, which can be modulated using different strains, as well as culture conditions such as temperature, pH, agitation, carbon source, and other medium components. The aim of this research was to obtain levan in SSF using rapeseed meal as the main substrate and different Bacillus subtilis natto strains. A new bioreactor for SSF was designed. Suitable methods for product separation and purification were also investigated. The purification process was performed with low-pressure liquid chromatography, using different types of column fillers. The molecular weight distribution of levan produced in the SSF process was determined using gel permeation chromatography, and 1H NMR (Proton nuclear magnetic resonance) was used to identify levan. We observed some differences in the molecular weight range of levan obtained from the cultivation of Bacillus strains in submerged fermentation and SSF. Various molecular weight levans may have different applications due to their specific properties.
Recent Publications
1. Esawy M A, Abdel-Fattah A M, Ali M M, Helmy W A, Salama B M, Taie H A A, Hasheman AM, Awad G E A (2013) Levansucrase optimization using solid state fermentation and levan biological activities studies. Carbohydrate Polymers 96: 332–341.
2. Kreyenschulte D, Krull R, Margaritis A (2012) Recent advances in microbial biopolymer production and purification. Critical Reviews in Biotechnology 34: 1–15.
3. Porras-Domínguez JR, Ávila-Fernández A, Miranda-Molina A, Rodríguez-Alegría ME, López Munguía A (2015) Bacillus subtilis 168 levansucrase (SacB) activity affects average levan molecular weight. Carbohydrate Polymers 132: 338–344.
4. Öner ET, Hernández L, Combie J (2016) Review of Levan polysaccharide: from a century of past experiences to future prospects. Biotechnology Advances 34: 827–844.
5. Thomas L, Larroche C, Pandey A (2013) Current developments in solid-state fermentation. Biochemical Engineering Journal 81: 146–161.