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Investigation of effects of various organic pollutants upon the exopolysaccharides (EPSs) produced by some Pseudomonas spp. strains
New Biotechnology · Volume 25S · September 2009
Response surface methodology obtained the mathematical models for xylitol yield (Yp, Y1 ), specific cell growth rate (µx , Y2 ) and specific xylitol production rate (µp , Y3 ): Y1 = 0.37367 − 0.1252X1 − 0.013057X2 − 0.040602X1 X1 −0.12185X2 X2 − 0.091825X1 X2 Y2 = 0.025667 − 0.01595X1 + 0.00469454X2 + 0.00791667X12 +0.00441667X22 Y3 = 0.016353 − 0.015430X1 + 0.013265X12 The independent variables were initial cell concentration (X1 ) and initial sugar concentration (X2 ), respectively. The responses (Yp , µx , µp ) were favored using 0.607 g/L of initial cell concentration and 58.5 g/L of initial total sugar concentration. Thus, the estimated values for Yp , µx and µp were, 0.471 g/g, 0.0515 h−1 and 0.0451 gxylitol /gcell h, respectively. In general, decreasing the initial cell concentration improved both specific cell growth and xylitol production rates and also xylitol yield. These facts could be related to the oxygen availability in the fermentation medium, which was indirectly related to the balance between the initial cells and sugar concentration. doi:10.1016/j.nbt.2009.06.596
3.1.52 Alternative protocols testing for sugarcane hemicellulosic hydrolysate detoxification P. Arruda ∗ , R.C.L.B. Rodrigues, M. Felipe University of São Paulo, Lorena, Brazil
The acid hydrolysis is the most employed method for obtaining hemicellulosic hydrolysate from lignocellulosic materials. This process requiring high-pressure and temperature generates fermentable sugar. Also, it could release sugar degradation product as furfural and 5-hydroxymethlylfurfural (HMF) and others toxic compounds (formic, levulinic and acetic acids and phenolic compounds). In general, the phenolic compounds and the acetic acid are present in high amount in the hemicellulosic hydrolysates. These compounds could be considered the most inhibitors during a fermentation process because of their effects on biological membrane permeability loss and ATP exhaustion, respectively. The aim of this work was to reduce the toxic compounds in the sugarcane hemicellulosic hydrolysate. It was evaluated three different detoxification protocols. The first one was made by increasing the initial hydrolysate pH from 0.5 to 7.0 with CaO following its reduction to pH 2.5 with H3 PO4 and subsequent hydrolysate treatment with active charcoal adsorption (1% w/v) in Erlenmeyer flasks on a rotatory shaker at 200 rpm, 60◦ C, for 30 min. The second protocol used vegetable-origin polymer flocculation technique. In this case, after increasing the initial hydrolysate pH (0.50) to 8.0 with CaO, the hydrolysate was treated with 15% v/v of vegetable-origin polymer in Erlenmeyer flasks on a rotatory shaker at 200 rpm, 45◦ C, for 45 min. The third protocol used a sequence of three ion exchange resins (A-860S; A500PS and C-150Purolite® ) using resin and hydrolysate ratio of 1:2 v/v. The resin
treatment was carried out in Erlenmeyer flasks on a rotatory shaker at 200 rpm, 30◦ C, for one hour. The sugar, acetic acid, furfural and HMF were analyzed by high liquid performance chromatography (HPLC) technique and the total phenolic compounds by Klason method (ASTM.D.1106-56). The sugarcane hemicellulosic hydrolysate without treatment had the following partial composition (g/L): xylose (72.4), arabinose (6.8), glucose (9.7), acetic acid (3.6), total phenolic compounds (12.7), furfural (0.08) and HMF (0.07). The phenolic compounds removal (92.4%) was improved using ion exchange resins, which was about 18% higher than the active charcoal and vegetable-origin polymer treatments. Also, the furfural (66.1%) and HMF (74.6%) removal was favored by ion exchange resins treatment. The acetic acid removal was 48.5, 28.0 and 18.1% using ion exchange resins, active charcoal and vegetable-origin polymer, respectively. Therefore, vegetable-origin polymer treatment could be considered in future researches by its low cost, biodegradability and easy handling. doi:10.1016/j.nbt.2009.06.597
3.1.53 Investigation of effects of various organic pollutants upon the exopolysaccharides (EPSs) produced by some Pseudomonas spp. strains D. Onbasli 1,∗ , B. Aslim 2 1
2
Kastamonu University, Kastamonu, Turkey Gazi University, Ankara, Turkey
In this study, production, isolation and characterization of the exopolysaccharides produced by the organic pollutant-degrading bacteria B1, Pseudomonas fluorescens B5, Pseudomonas stutzeri B11 and Pseudomonas putida B15 which had been seen to produce exopolymers of potential interest in biotechnological applications were examined. To initiate the observation of the organic pollutants—polymer interactions, the yield and properties of their extracellular polysaccharide were researched. Produced of these strains in nutrient broth (NB) medium, EPSs were grown and used as control value which ranged from 75 mg L−1 to 41 mg L−1 . Also, isolated ones had exhibited high production of EPSs in the presence of various organic pollutants in mineral salt medium (MSM) as a sole carbon source. EPS production by the four strains ranged from 40 mg L−1 to 8 mg L−1 . Monosaccharide compositions of EPS produced by these cultures were analyzed by HPLC. Results indicated that EPSs of strains contained neutral sugars and acetylated amino sugars. The neutral sugars in the EPS were mainly composed of glucose, arabinose, glycerol and ribose. The presence of galactronic acid, N-acetyl-D-galactosamine and N-acetyl-D-glucosamine indicated the acidic nature of the polysaccharide. Glycerol dominated the EPS produced by these strains. Monomer composition of control EPSs turned to different structures in the presence of various organic pollutants. Diversities and concentration of organic compounds as carbon source affected the composition of EPS produced by some Pseudomonas spp. cultures. doi:10.1016/j.nbt.2009.06.598
www.elsevier.com/locate/nbt S267
Response surface methodology obtained the mathematical models for xylitol yield (Yp, Y1 ), specific cell growth rate (µx , Y2 ) and specific xylitol production rate (µp , Y3 ): Y1 = 0.37367 − 0.1252X1 − 0.013057X2 − 0.040602X1 X1 −0.12185X2 X2 − 0.091825X1 X2 Y2 = 0.025667 − 0.01595X1 + 0.00469454X2 + 0.00791667X12 +0.00441667X22 Y3 = 0.016353 − 0.015430X1 + 0.013265X12 The independent variables were initial cell concentration (X1 ) and initial sugar concentration (X2 ), respectively. The responses (Yp , µx , µp ) were favored using 0.607 g/L of initial cell concentration and 58.5 g/L of initial total sugar concentration. Thus, the estimated values for Yp , µx and µp were, 0.471 g/g, 0.0515 h−1 and 0.0451 gxylitol /gcell h, respectively. In general, decreasing the initial cell concentration improved both specific cell growth and xylitol production rates and also xylitol yield. These facts could be related to the oxygen availability in the fermentation medium, which was indirectly related to the balance between the initial cells and sugar concentration. doi:10.1016/j.nbt.2009.06.596
3.1.52 Alternative protocols testing for sugarcane hemicellulosic hydrolysate detoxification P. Arruda ∗ , R.C.L.B. Rodrigues, M. Felipe University of São Paulo, Lorena, Brazil
The acid hydrolysis is the most employed method for obtaining hemicellulosic hydrolysate from lignocellulosic materials. This process requiring high-pressure and temperature generates fermentable sugar. Also, it could release sugar degradation product as furfural and 5-hydroxymethlylfurfural (HMF) and others toxic compounds (formic, levulinic and acetic acids and phenolic compounds). In general, the phenolic compounds and the acetic acid are present in high amount in the hemicellulosic hydrolysates. These compounds could be considered the most inhibitors during a fermentation process because of their effects on biological membrane permeability loss and ATP exhaustion, respectively. The aim of this work was to reduce the toxic compounds in the sugarcane hemicellulosic hydrolysate. It was evaluated three different detoxification protocols. The first one was made by increasing the initial hydrolysate pH from 0.5 to 7.0 with CaO following its reduction to pH 2.5 with H3 PO4 and subsequent hydrolysate treatment with active charcoal adsorption (1% w/v) in Erlenmeyer flasks on a rotatory shaker at 200 rpm, 60◦ C, for 30 min. The second protocol used vegetable-origin polymer flocculation technique. In this case, after increasing the initial hydrolysate pH (0.50) to 8.0 with CaO, the hydrolysate was treated with 15% v/v of vegetable-origin polymer in Erlenmeyer flasks on a rotatory shaker at 200 rpm, 45◦ C, for 45 min. The third protocol used a sequence of three ion exchange resins (A-860S; A500PS and C-150Purolite® ) using resin and hydrolysate ratio of 1:2 v/v. The resin
treatment was carried out in Erlenmeyer flasks on a rotatory shaker at 200 rpm, 30◦ C, for one hour. The sugar, acetic acid, furfural and HMF were analyzed by high liquid performance chromatography (HPLC) technique and the total phenolic compounds by Klason method (ASTM.D.1106-56). The sugarcane hemicellulosic hydrolysate without treatment had the following partial composition (g/L): xylose (72.4), arabinose (6.8), glucose (9.7), acetic acid (3.6), total phenolic compounds (12.7), furfural (0.08) and HMF (0.07). The phenolic compounds removal (92.4%) was improved using ion exchange resins, which was about 18% higher than the active charcoal and vegetable-origin polymer treatments. Also, the furfural (66.1%) and HMF (74.6%) removal was favored by ion exchange resins treatment. The acetic acid removal was 48.5, 28.0 and 18.1% using ion exchange resins, active charcoal and vegetable-origin polymer, respectively. Therefore, vegetable-origin polymer treatment could be considered in future researches by its low cost, biodegradability and easy handling. doi:10.1016/j.nbt.2009.06.597
3.1.53 Investigation of effects of various organic pollutants upon the exopolysaccharides (EPSs) produced by some Pseudomonas spp. strains D. Onbasli 1,∗ , B. Aslim 2 1
2
Kastamonu University, Kastamonu, Turkey Gazi University, Ankara, Turkey
In this study, production, isolation and characterization of the exopolysaccharides produced by the organic pollutant-degrading bacteria B1, Pseudomonas fluorescens B5, Pseudomonas stutzeri B11 and Pseudomonas putida B15 which had been seen to produce exopolymers of potential interest in biotechnological applications were examined. To initiate the observation of the organic pollutants—polymer interactions, the yield and properties of their extracellular polysaccharide were researched. Produced of these strains in nutrient broth (NB) medium, EPSs were grown and used as control value which ranged from 75 mg L−1 to 41 mg L−1 . Also, isolated ones had exhibited high production of EPSs in the presence of various organic pollutants in mineral salt medium (MSM) as a sole carbon source. EPS production by the four strains ranged from 40 mg L−1 to 8 mg L−1 . Monosaccharide compositions of EPS produced by these cultures were analyzed by HPLC. Results indicated that EPSs of strains contained neutral sugars and acetylated amino sugars. The neutral sugars in the EPS were mainly composed of glucose, arabinose, glycerol and ribose. The presence of galactronic acid, N-acetyl-D-galactosamine and N-acetyl-D-glucosamine indicated the acidic nature of the polysaccharide. Glycerol dominated the EPS produced by these strains. Monomer composition of control EPSs turned to different structures in the presence of various organic pollutants. Diversities and concentration of organic compounds as carbon source affected the composition of EPS produced by some Pseudomonas spp. cultures. doi:10.1016/j.nbt.2009.06.598
www.elsevier.com/locate/nbt S267