Exobiopolymer production of Ophiocordyceps dipterigena BCC 2073: optimization, production in bioreactor and characterization

Abstract

BackgroundBiopolymers have various applications in medicine, food and petroleum industries. The ascomycetous fungus Ophiocordyceps dipterigena BCC 2073 produces an exobiopolymer, a (1→3)-β-D-glucan, in low quantity under screening conditions. Optimization of O. dipterigena BCC 2073 exobiopolymer production using experimental designs, a scale-up in 5 liter bioreactor, analysis of molecular weight at different cultivation times, and levels of induction of interleukin-8 synthesis are described in this study.ResultsIn order to improve and certify the productivity of this strain, a sequential approach of 4 steps was followed. The first step was the qualitative selection of the most appropriate carbon and nitrogen sources (general factorial design) and the second step was quantitative optimization of 5 physiological factors (fractional factorial design). The best carbon and nitrogen source was glucose and malt extract respectively. From an initial production of 2.53 g·L-1, over 13 g·L-1 could be obtained in flasks under the improved conditions (5-fold increase). The third step was cultivation in a 5 L bioreactor, which produced a specific growth rate, biomass yield, exobiopolymer yield and exobiopolymer production rate of 0.014 h-1, 0.32 g·g-1 glucose, 2.95 g·g biomass-1 (1.31 g·g-1 sugar), and 0.65 g.(L·d)-1, respectively. A maximum yield of 41.2 g·L-1 was obtained after 377 h, a dramatic improvement in comparison to the initial production. In the last step, the basic characteristics of the biopolymer were determined. The molecular weight of the polymer was in the range of 6.3 × 105 - 7.7 × 105 Da. The exobiopolymer, at 50 and 100. μg·mL-1, induced synthesis in normal dermal human fibroblasts of 2227 and 3363 pg·mL-1 interleukin-8 respectively.ConclusionsHigh exobiopolymer yield produced by O. dipterigena BCC 2073 after optimization by qualitative and quantitative methods is attractive for various applications. It induced high IL-8 production by normal dermal fibroblasts, which makes it promising for application as wound healing material. However, there are still other possible applications for this biopolymer, such as an alternative source of biopolymer substitute for hyaluronic acid, which is costly, as a thickening agent in the cosmetic industry due to its high viscosity property, as a moisturizer, and in encapsulation.

Production and Characterization of Exopolysaccharide From Marine Moderately Halophilic Bacterium Halomonas Smyrnensis SVD Iii

“…Optimization of production of EPS and its characterization from Ophiocordyceps dipterigena was studied [12]. Optimization of different nutrient media for the production of EPS by Bacllus subtilis has been described [20].…”

“…The purified EPS was characterized using fourier-transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS) [6,12,18,31].…”

“…They play an important role in protection against desiccation [2] and also useful in forming biofilms [3,4]. Their various applications include use as gelling agents, biosurfactants, emulsifiers, viscosifiers [5][6][7], biosorbants [8,9], biologically active antimicrobials, anticancer agents and antioxidants [10][11][12][13].…”

Production and characterization of exopolysaccharides in mycelial culture ofCordyceps sinensisfungus Cs-HK1 with different carbon sources

“…In addition to mycelial biomass, significant amount of exopolysaccharides (EPS) has been produced by the Cs-HK1 mycelial culture in the liquid medium. Microbial EPS produced by liquid fermentation have found wide industrial applications especially as the food and biomedical fields such as xanthan and gellan as food additives, scleroglucan as laxative tablet coating, and dextran as plasma expanders [6]. More recently there has been increasing interest in the pharmaceutical applications of microbial EPS [7].…”

Antioxidant and antibacterial activities of exopolysaccharides produced by lactic acid bacteria isolated from yogurt

“…Recently, lactic acid bacteria (LAB) have received attention for their exopolysaccharides (EPS) producing ability. A broad range of EPS from LAB with variable functionality can have a wide range of industrial application (Cerning & Marshall, 1999) as gelling agents, biosurfactants, emulsifiers, viscosifiers (Poli, Anzelmo, & Nicolaus, 2010) and biosorbents (de Oliveira Martins, de Almeida, & Ferreira Leite, 2008) In addition, EPS play important roles in human health owing to their antitumor, antioxidant, anti-ulcer and antibacterial activities (Kocharin, Rachathewee, Sanglier, & Prathumpai, 2010;Liu, Chu, Chou, & Yu, 2011) However, owing to the lack of expansive knowledge on EPS from food-associated LAB, EPS have remained largely underexploited. Fermentation is a very versatile process technology for producing value added products such as microbial biopolymers and since fermentation Copyright ©2018 ISEKI-Food Association (IFA) 10.…”