• Microbiology and Biotechnology Letters
• /
• v.24 no.1
• /
• pp.111-118
• /
• 1996

For the screening and the development of the new bio-material, cultural conditions for the exo-biopolymer (EBP) production throught the submerged cultivation of Ganoderma lucidum mycelium were investigated. Also, the fractionations and the purifications of the exo-biopolymer were carried out and the chemical compositions of the exo-biopolymer were examined. The optimal culture conditions for the exo-biopolymer production were pH 5.0, 30$^{\circ}C$ and 100 rpm of agitation speed in the medium containing of 5% (w/v) glucose, 0.5%(w/v) yeast extract, 0.1% (w/v) ($(NH_4)_2HPO_4$, and 0.05% (w/v) $KH_2PO_4$. In the flask cultivation for 7 days under these conditions, the concentration of the maximum exo-biopolymer and the cell mass were 15.4g/l and 18.8g/l, respectively. The specific growth rate was 0.039 $hr^{-1}$. In addition, the substrate consumption rate, and the exo-biopolymer production rate were 0.043$gg^{-1}$$hr^{-1}$ and 0.025$gg^{-1}$$hr^{-1}$, respectively. The exo-biopolymer was fractionated into BWS (water soluble exo-biopolymer) and BWI (water insoluble exo-biopolymer) by the water extraction, and the sugar contents of two fractions were higher than 97% (based on dry basis). The components sugar of BWS and BWI fractions were glucose, galactose, mannose, xylose, and fucose. Their molar ratios were 3.6:1.5:2.1:0.5: trace and 2.9:3.1:2.0:1.6:0.3, respectively.

• Korean Journal of Environmental Biology
• /
• v.18 no.1
• /
• pp.199-203
• /
• 2000

A bacterium that produce biopolymer was isolated from Gochujang, one of Korean traditional fermented foods, and identified as Bacillus licheniformis. The production of biopolymer was highest and 34mg/250ml, when the baterium was cultivated in condition of sucrose 6.0%, Yeast extract 0.1%, peptone 0.l%, NaCl 3.0%, and pH 6.0. The 1% solution of this biopolymer was able to form a translucent and glossy film. And the solution of biopolymer was found to precipitate Kaolin solution and also stabilize the suspension of lactic acid bacteria within the test range of 0.25-1.00%. [Bacillus licheniformis, Biopolymer].

• 한국생물공학회:학술대회논문집
• /
• 2003.10a
• /
• pp.243-245
• /
• 2003

The continuous fermentation process for exe-biopolymer production with Cordyceps militaris has been developed in this research. With the change of dilution rate, biopolymer production has been changed and the maximal biopolymer production has been achieved when the dilution rate was 0.0225/hr. The maximum mycelium concentration and biopolymer concentration were 8 g/L and 4.2 g/L, respectively.

• Korean Journal of Food Science and Technology
• /
• v.29 no.1
• /
• pp.138-144
• /
• 1997

A new biopolymer YU-122 from Metarrhizium anisopliae (Metschn.) Sorok consisting of glucose and galactose was tested for its physical properties and flow behavior characteristics. Xanthan gum showed slightly higher viscosity than biopolymer YU-122. Viscosity of biopolymer YU-122 at various pHs and temperatures was also tested. The viscosity of biopolymer YU-122 was very stable up to pH 11 and $60^{\circ}C$, indicating that it has a great possibility for the application such as food additives, emulsifier, and drug release agents. Flow behavior index (n) from Power Law equation is 0.173. Biopolymer YU-122 solution was a pseudoplastic non-Newtonian fluid, which indicated that it had one or more side chains. When biopolymer YU-122 was used as a emulsifier, it stabilized the emulsion up to 120 hours, which was much better than xanthan gum. The biopolymer YU-122 could form an excellent but less clear film compared with xanthan and pullulan.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.29 no.2
• /
• pp.198-203
• /
• 2000

A highly viscous biopolymer from Bacillus coagulans CE-74 was purified and its rheological properties were studied The rheological properties of biopolymers produced by Bacillus coagulans CE-74 were studied at the temperature ranges with 20~8$0^{\circ}C$, at the concentration of 0.5~4.0%, at the pH ranges from 3 to 1 and at the shear rate fo 7.34~73.38 sec-1. The apparent viscosity of biopolymer was decreased with increasing shear rate, and thereby biopolymer showed pseudoplastic characteristics. Biopolymer solution showed a characteristic of non-Newtonian fluid properties. At the concentration of 1%, the consistency index and the flow behavior index were shown at 2.64 poise. sec11 and 0.8571, respectively. All dispersions were pseudoplastic fluids described accurately by Herschel-Bulkley model. The change of the biopolymer viscosity on pH showed the highest value at the pH 7.0 and it showed lower at acidic conditon that at alkaline condition comparatively.

• Structural Engineering and Mechanics
• /
• v.88 no.2
• /
• pp.179-188
• /
• 2023

The mechanical behaviours of biopolymer-treated soil depend on the formation of soil-biopolymer matrices. In this study, various biopolymers(e.g., xanthan gum (XG), locust bean gum (LBG), sodium alginate (SA), agar gum (AG), gellan gum (GE) and carrageenan kappa gum (KG) are selected to treat three types of natural soil at different concentrations (e.g., 1%, 2% and 3%) and curing time (e.g., 4-365 days), and reveal the reinforcement effect on natural soil by using unconfined compression tests. The results show that biopolymer-treated soil obtains the maximum unconfined compressive strength (UCS) at curing 14-28 days. Although the UCS of biopolymer-treated soil has a 20-30% reduction after curing 1-year compared to the maximum value, it is still significantly larger than untreated soil. In addition, the UCS increment ratio of biopolymer-treated soil decreases with the increase of biopolymer concentration, and there exists the optimum concentration of 1%, 2-3%, 2%, 1% and 2% for XG, SA, LBG, KG and AG, respectively. Meanwhile, the optimum initial moisture content can form uniformly biopolymer-soil matrices to obtain better reinforcement efficiency. Furthermore, the best performance in increasing soil strength is XG following SAand LBG, which are significantly better than AG, KG and GE.

• 한국생물공학회:학술대회논문집
• /
• 2003.10a
• /
• pp.249-251
• /
• 2003

The effects of fermentor types on biopolymer production with Cordyceps militaris has been studied in this articles. Since the shear stresses of stirred tank ferementor and bubble column fermentor were different, the mycelium growth and biopolymer production were different. The mycerial growth was high with the bubble column fermentor for the early stage but biopolymer production was lower than that with stirred tank fermentor. The production of biopolymer was closely related to shear stress to the cells and biopolymer production was increased with increased shear stress.

• Geomechanics and Engineering
• /
• v.29 no.3
• /
• pp.259-267
• /
• 2022

The rheological and penetration characteristics of sodium alginate and xanthan gum aqueous solutions were analyzed for the development of biopolymer-based injection materials. The results of viscosity measurements for the rheological characteristics analysis show that all aqueous biopolymer solutions exhibit a tendency for shear-thinning, i.e., the apparent viscosity decreases as the shear rate increases. In addition, a regression analysis using several models (Power-law, Casson, Sisko, and Cross) was applied to the shear-thinning fluid analysis results, the highest accuracy was determined by applying the power-law model. The micromodel experiment for the penetration characteristics analysis determined that all biopolymer aqueous solutions show higher pore saturation than water, and that pore saturation tends to increase as the flow rate and concentration increases. When comparing the rheological and penetration characteristics of the biopolymer aqueous solution used in this study, the xanthan gum aqueous solution showed a fully developed shear-thinning tendency, unlike the sodium alginate aqueous solution. This tendency is considered to have the advantage of enhancement injectability and pore saturation.

• KSBB Journal
• /
• v.13 no.5
• /
• pp.554-560
• /
• 1998

Biopolymer from alkaline-tolerant Bacillus so. was purified, and its physico-chemical and structural properties were investigated. Crude biopolymer, precipitated by acetone from culture broth was fractionated into two fractions by gel chromatography on Sephadex G-200. Among two fractions, one fraction(PS I), which an acidic biopolymer precipitated by the CPC(cetylpyridinium chloride) treatment was studied further. PS I fraction had carboxyl groups and was positive at color reaction of sugar. PS I fraction also showed UV absorbance at 190-225nm. The purified acidic biopolymer was composed of 4% glucose, 8% glucosamine and 88% glutamic acid. Sugar components of the purified acidic biopolymer seemed to be linked to PGA(polyglutamic acid) which existed in the from of ${\gamma}$-peptide bond. By the results of Smith degradation of sugar components, glucose and glucosamine was bound by 1,3 glocosidic linkage. Therefore, this biopolymer was a glycopeptide, oligosaccaride ${\gamma}$-PGA. We concluded that the equivalent weight and the molecular weight of this biopolymer were estimated as about 171 and 5x105 dalton, respectively.

• Applied Biological Chemistry
• /
• v.43 no.2
• /
• pp.81-85
• /
• 2000

Screening was performed to isolate biopolymer-producing microorganisms from natural sources. The bacteriological characteristics of this strain and physicochemical properties of the biopolymer produced were investigated. The bacterial strain was identified as a Bacillus coagulans. Crude biopolymer treated with ethanol and actone was purified to fraction I and II by ion exchange chromatography and gel chromatography (Shephadex G-100 and Shepharose CL-2B). Analysis of chemical composition and various color reaction revealed that the polymer is composed of amino acids. It was confirmed that fraction II is a homopolymer of glutamic acid and fraction I is a homopolymer of lysine by analysis data of amino acid analyzer, GC and IR.