- Email: [email protected]
Optimization of flocculation conditions using chitosan in mannanase production
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Abstracts / Journal of Biotechnology 185S (2014) S37–S125
development time and cost. Therefore the model predicts biomass growth, O2 - and glycerin consumption. http://dx.doi.org/10.1016/j.jbiotec.2014.07.194 Optimization of flocculation conditions using chitosan in mannanase production Ercan Yatmaz, Ercan Karahalil, Mustafa Germec, Irfan Turhan ∗ Akdeniz University, Faculty of Engineering, Department of Food Engineering, Antalya, Turkey E-mail address: [email protected] (I. Turhan). Mannanases, which have many usages in the food and other industries, can be produced by fermentation in a stirred tank bioreactor. In order to purify of an enzyme from fermentation broth, flocculation is extensively used for primary enzyme separation. This low-cost technology is relatively slow and suitable only for large flocs. In this research, chitosan was used to be flocculation agent and to optimize chitosan flocculation conditions using response surface method (RSM). The amount of chitosan (40–80 mg/L), agitation (0–200 rpm) and time (20–40 min) were determined to be flocculation parameters. Fermented broth was produced by recombinant Aspergillus sojae in the 2 L bioreactor at 30 ◦ C for 10 day and filtered before flocculation. Broth was then centrifuged and enzyme activity was performed to carry out the differences between the studies. The initial enzyme activity was adjusted to 100 U/ml. At the end of the flocculation in the optimized conditions of 40 mg/L chitosan, 0 rpm and 30 min, enzyme activity was increased at 171.21%. Results showed that flocculation with chitosan is a useful application step for mannanase purification from fermented broth by recombinant Aspergillus sojae. Note: This work was supported by grants from TUBITAK (112 O 167). http://dx.doi.org/10.1016/j.jbiotec.2014.07.195 Biosensors Electrochemical detection of bisphenol a using novel sensor arrays Zehra Ölc¸er 1,∗ , Canan Do˘gan 2 , Yıldız Uluda˘g 2 1
Department of Chemistry, Gebze Institute of Technology, Gebze, Turkey 2 UEKAE – BILGEM – The Scientific and Technological Research Council of Turkey (TUBITAK), Gebze, Turkey
acceptable threshold level of BPA in drinking water. This result indicate that this new electrode array provides a convenient tool for BPA testing in water samples and studies will continue to build a portable BPA sensor. http://dx.doi.org/10.1016/j.jbiotec.2014.07.196 Biotechnology & Ethics Biodegradation of microcystic toxins with manganese peroxidase as biocatalyst and further degradation of microcystic toxins with polythiophene-Gd2YbSbO7 as photocatalyst Jingfei Luan, Biaohang Chen ∗ State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, China E-mail address: [email protected] (B. Chen). The preliminary biodegradation results of microcystic toxins were achieved with manganese peroxidase as biocatalyst. The results indicated that the maximum removal percentage of microcystic toxins was 69.8% after 28 min of reaction time and the maximum experimental parameters were as following: hydrogen peroxide 107.2 mol/L, enzyme 77.5 U/mL, pH value 4.8 and microcystic toxins concentration 50.1 mg/L. Lactuca sativa and Artemia salina were used for evaluating the toxicity of the products. The manganese peroxidase was very efficient for removal of microcystic toxins, and the products which were obtained after enzymatic removal showed high toxicity. The lethal concentration LC50 which was achieved for Artemia salina was 47.7% and the inhibition concentration IC50 which was gained for Lactuca sativa was 23.7%. Above results showed the importance of toxicological reckon after enzymatic treatment. Further degradation of microcystic toxins was realized. The composite catalyst polythiophene-Gd2YbSbO7 was synthetized for the first time. Complete photocatalytic degradation of microcystic toxins over the polythiophene-Gd2YbSbO7 was realized under visible light irradiation for 32 min. The photocatalytic degradation of microcystic toxins followed the first-order reaction kinetics. The degradation pathway of microcystic toxins was achieved. Acknowledgment This work was supported by the National Natural Science Foundation of China (No. 21277067). http://dx.doi.org/10.1016/j.jbiotec.2014.07.197
E-mail address: [email protected] (Z. Ölc¸er). Bisphenol A (BPA) is harmful to living organisms as a typical endocrine disruptor, and hence its migration from the package to the beverage is considered as a risk. According to the literature one disadvantage of electrochemical detection of BPA is its higher detection limit. In the current study, by utilising newly designed electrode arrays, this statement has been put into testing. Three electrode arrays were designed and fabricated by the evaporation of Ti/Au layer on glass slides. It was found that when Au is used as quasi-reference electrode, the arrays with shared reference and counter electrodes results in faster electron transfer kinetics and prevents the potential change with respect to scan rate, and hence advantageous with respect to the conventional electrodes. Later the designed electrodes (d = 2.5 mm) have been used for the chronoamperometric detection of BPA (0.5 V), that resulted in a detection limit of 10 ng/ml BPA with a linear range between 10 and 1000 ng/ml. The detection limit obtained is well below the
Education & Biotechnology Researches on the consumers’ behaviour of organic food. Case study, Romania–Bulgaria cross border area Daniela Cretu ∗ , Andrei Radu Iova, Iulian Alecu University of Agronomic Sciences and Veterinary Medicine Bucharest, Romania E-mail address: [email protected] (D. Cretu). The research problem which was the basis of this market survey is to collect information about the current trends and needs of existing on the food products market in Romania–Bulgaria cross border area and especially about the attitude toward these products, which form the basis for the future collaboration initiatives with the traders and commercial changes in this area. The study was made
Abstracts / Journal of Biotechnology 185S (2014) S37–S125
development time and cost. Therefore the model predicts biomass growth, O2 - and glycerin consumption. http://dx.doi.org/10.1016/j.jbiotec.2014.07.194 Optimization of flocculation conditions using chitosan in mannanase production Ercan Yatmaz, Ercan Karahalil, Mustafa Germec, Irfan Turhan ∗ Akdeniz University, Faculty of Engineering, Department of Food Engineering, Antalya, Turkey E-mail address: [email protected] (I. Turhan). Mannanases, which have many usages in the food and other industries, can be produced by fermentation in a stirred tank bioreactor. In order to purify of an enzyme from fermentation broth, flocculation is extensively used for primary enzyme separation. This low-cost technology is relatively slow and suitable only for large flocs. In this research, chitosan was used to be flocculation agent and to optimize chitosan flocculation conditions using response surface method (RSM). The amount of chitosan (40–80 mg/L), agitation (0–200 rpm) and time (20–40 min) were determined to be flocculation parameters. Fermented broth was produced by recombinant Aspergillus sojae in the 2 L bioreactor at 30 ◦ C for 10 day and filtered before flocculation. Broth was then centrifuged and enzyme activity was performed to carry out the differences between the studies. The initial enzyme activity was adjusted to 100 U/ml. At the end of the flocculation in the optimized conditions of 40 mg/L chitosan, 0 rpm and 30 min, enzyme activity was increased at 171.21%. Results showed that flocculation with chitosan is a useful application step for mannanase purification from fermented broth by recombinant Aspergillus sojae. Note: This work was supported by grants from TUBITAK (112 O 167). http://dx.doi.org/10.1016/j.jbiotec.2014.07.195 Biosensors Electrochemical detection of bisphenol a using novel sensor arrays Zehra Ölc¸er 1,∗ , Canan Do˘gan 2 , Yıldız Uluda˘g 2 1
Department of Chemistry, Gebze Institute of Technology, Gebze, Turkey 2 UEKAE – BILGEM – The Scientific and Technological Research Council of Turkey (TUBITAK), Gebze, Turkey
acceptable threshold level of BPA in drinking water. This result indicate that this new electrode array provides a convenient tool for BPA testing in water samples and studies will continue to build a portable BPA sensor. http://dx.doi.org/10.1016/j.jbiotec.2014.07.196 Biotechnology & Ethics Biodegradation of microcystic toxins with manganese peroxidase as biocatalyst and further degradation of microcystic toxins with polythiophene-Gd2YbSbO7 as photocatalyst Jingfei Luan, Biaohang Chen ∗ State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, China E-mail address: [email protected] (B. Chen). The preliminary biodegradation results of microcystic toxins were achieved with manganese peroxidase as biocatalyst. The results indicated that the maximum removal percentage of microcystic toxins was 69.8% after 28 min of reaction time and the maximum experimental parameters were as following: hydrogen peroxide 107.2 mol/L, enzyme 77.5 U/mL, pH value 4.8 and microcystic toxins concentration 50.1 mg/L. Lactuca sativa and Artemia salina were used for evaluating the toxicity of the products. The manganese peroxidase was very efficient for removal of microcystic toxins, and the products which were obtained after enzymatic removal showed high toxicity. The lethal concentration LC50 which was achieved for Artemia salina was 47.7% and the inhibition concentration IC50 which was gained for Lactuca sativa was 23.7%. Above results showed the importance of toxicological reckon after enzymatic treatment. Further degradation of microcystic toxins was realized. The composite catalyst polythiophene-Gd2YbSbO7 was synthetized for the first time. Complete photocatalytic degradation of microcystic toxins over the polythiophene-Gd2YbSbO7 was realized under visible light irradiation for 32 min. The photocatalytic degradation of microcystic toxins followed the first-order reaction kinetics. The degradation pathway of microcystic toxins was achieved. Acknowledgment This work was supported by the National Natural Science Foundation of China (No. 21277067). http://dx.doi.org/10.1016/j.jbiotec.2014.07.197
E-mail address: [email protected] (Z. Ölc¸er). Bisphenol A (BPA) is harmful to living organisms as a typical endocrine disruptor, and hence its migration from the package to the beverage is considered as a risk. According to the literature one disadvantage of electrochemical detection of BPA is its higher detection limit. In the current study, by utilising newly designed electrode arrays, this statement has been put into testing. Three electrode arrays were designed and fabricated by the evaporation of Ti/Au layer on glass slides. It was found that when Au is used as quasi-reference electrode, the arrays with shared reference and counter electrodes results in faster electron transfer kinetics and prevents the potential change with respect to scan rate, and hence advantageous with respect to the conventional electrodes. Later the designed electrodes (d = 2.5 mm) have been used for the chronoamperometric detection of BPA (0.5 V), that resulted in a detection limit of 10 ng/ml BPA with a linear range between 10 and 1000 ng/ml. The detection limit obtained is well below the
Education & Biotechnology Researches on the consumers’ behaviour of organic food. Case study, Romania–Bulgaria cross border area Daniela Cretu ∗ , Andrei Radu Iova, Iulian Alecu University of Agronomic Sciences and Veterinary Medicine Bucharest, Romania E-mail address: [email protected] (D. Cretu). The research problem which was the basis of this market survey is to collect information about the current trends and needs of existing on the food products market in Romania–Bulgaria cross border area and especially about the attitude toward these products, which form the basis for the future collaboration initiatives with the traders and commercial changes in this area. The study was made