- Email: [email protected]
Production of polyhydroxyalkanoates from hydrolyzed corn oil by high cell density culture of Pseudomonas putida
Abstracts / Journal of Biotechnology 136S (2008) S506–S518
maximum enrichment ratio (9.86) and removal rate (98.63%) was obtained when the optimum conditions of gas flow-rate, pH, surfactant concentration, load volume were 0.05 m3 /h, 4.0, 0.16 g/l, 1.0 l, respectively. Comparing with the commonly used surfactantsodium dodecyl sulfate, DBAS would not leave Na+ in the aqueous solutions (Morgan and Wiesmann, 2002), thus a new idea was put forward for removing ions or salts by foam fractionation.
S509
Sun J, Xu, W.B., 2004. Particle Swarm Optimization with Particles Having Quantum Behavior. Proceedings 2004 Congress on Evolutionary Computation, pp. 325–331. Xu, W.B., Sun, J., 2004. Efficient Scheduling of Task Graphs to Multiprocessors Using a Simulated Annealing Algorithm. DCABES 2004 Proceedings, vol. 1, pp. 435–439.
doi:10.1016/j.jbiotec.2008.07.631 V7-P-008
References Bustos, G., Moldes, A.B., Alonso, J.L., 2004. Optimization of d-lactic acid production by Lactobacillus coryniformis using response surface methodology. Food Microbiol. 21, 143–148. Morgan, G., Wiesmann, U., 2002. Foam fractionation of surfactant-containing rinsing water. Chem. Ing. Technol. 74, 453–457. Yenidunya, M.D., 2006. Recovery of Zn(II), Mn(II) and Cu(II) in aqueous solutions by foam fractionation with sodium dodecyl sulphate in combination with chelating agents. Sep. Sci. Technol. 41, 1741–1756.
doi:10.1016/j.jbiotec.2008.07.630 V7-P-007 The optimization algorithm based biotechnology information Xiaohong Kong 1,∗ , Haizhen Mo 2 , Wei Zhang 1 , Mingfu Zhao 1 1
School of Electrical and Mechanical, Henan Institute of Science and Technology, Xinxiang, 453003, Henan province, China 2 School of Food Science, Henan Institute of Science and Technology, Xinxiang, 453003, China Intelligent optimization algorithms are a set of bionic algorithms to resolve complicated problems, which are well characterized by its self-organizing, self-learning, self-adaptive, implicit parallelism and guided search etc. These algorithms have been widely used to solve complex issues of engineering technology, nonlinear optimization, structural design, parallel computing, social science as well as many other fields. By employing the advantages of the intelligent optimization algorithms, this paper deals with the important problem of task matching and scheduling. In order to make full use of the potential power of network computing system, tasks matching and scheduling is one of the critical challenges in this filed and is also NP-hard. Solving the problem is of great significance to the development and application of high performance computing. Considering the universality of intelligent optimization algorithms against particularity of the specific issues, the proposed algorithm adjusts evolution strategies and design special operator. Based on common characteristics of the evolutionary algorithm, designing evolutionary algorithms for the scheduling problem are further investigated.
Production of polyhydroxyalkanoates from hydrolyzed corn oil by high cell density culture of Pseudomonas putida Longan Shang 1,2,∗ , Min Jiang 2,3 , Zhi Yun 2 , Ho Nam Chang 3 1
Ningbo Institute of Technology, Zhejiang University, NingBo 315100, China 2 Korea Advanced Institute of Science and Technology, Daejeon 305701, Republic of Korea 3 College of Pharmacy and Life Science, Nanjing University of Technology, Nanjing 210009, China E-mail address: [email protected] (L. Shang).
There is considerable industrial interest in Poly(3-hydroxyalkanoates) (PHAs), but their cost is a major issue. To make PHAs production more economical, some researchers have tried to produce PHAs from inexpensive carbon sources such as plant oils. However their productivities were so low that they were impossible to be used for carrying out mass production. There were some flask cultures that had showed Pseudomonas putida being able to produce PHAs from hydrolyzed palm oil and hydrolyzed linseed oil (Annuar et al., 2007; Casini et al., 1997). Corn oil is a rich renewable source; however, there is no report on how to use corn oil to produce PHAs. This paper demonstrated that the medium-chain-length PHAs could be made effectively from the corn oil hydrolysate, an inexpensive and renewable carbon source, by high cell density cultures of P. putida under a phosphate limitation. Corn oil was hydrolyzed using lipase from Candida rugosa (Sigma 724 U/mg). The dissolved oxygen concentration was used as an online signal for feeding corn oil hydrolysate. Other detailed information on fermentation and analysis methods could be found in the previous work (Shang et al., 2007). The cell growth, MCL–PHAs accumulation and feeding strategies of corn oil hydrolysate in the cultures of P. putida were investigated in 5 L and 30 L fermentors respectively. In the 30-L scale fermentation, the final cell concentration and MCL–PHAs concentrations reached 103 and 28 g/L, which represents a MCL–PHAs productivity of 0.61 g/L h. It was confirmed by the NMR spectrum that this MCL–PHAs from corn oil hydrolysate contained 4 saturated and 3 unsaturated monomers with a chain length of 6–14 carbon atoms.
Keywords: Biotechnology; Intelligent optimization algorithms; Ant colony optimization; Evolutionary algorithms Acknowledgements References ´ T., Crainic, T.G., 2006. Benchmark-Problem instances for static task Davidovic, scheduling of task graphs with communication delays on homogeneous multiprocessor systems. Comput. OR 33 (8), 2155–2177. Kong, X.H., Xu, W.B., Liu, J., 2006a. A Permutation-Based Differential Evolution Algorithm Incorporating Simulated Annealing for Multiprocessor Scheduling with Communication Delays. International Conference on Computational Science, LNCS 3991. Kong, X.H., Sun. J., Xu, W.B., 2006b. Particle Swarm Algorithm for Tasks Scheduling in Distributed Heterogeneous System. Sixth International Conference on Intelligent System Design and Applications, p. 2. Kong, X.H., Sun, J., Xu, W.B., 2006c. Parallel Ant Colony Algorithm for Multiprocessor Scheduling with Communication Delays. 2006 International Symposium and Distributed Computing and Applications to Electron, Engineering and Science, p. 1.
This work was funded by the Ningbo Natural Science Foundation (2006A610043), and the Science and Technology Department of Zhejiang province (2007R10020).
References Annuar, M., Suffian, M., Tna, I.K.P., Ibrahim, S., Ramachandran, K.B., 2007. Production of medium-chain length poly(3-hydroxyalkanoates) from crude fatty acids mixture by Pseudomonas putida. Food Bioprod. Process. 85 (2), 104–109. Casini, E., de Rijk, T.C., de Waard, P., Eggink, G., 1997. Synthesis of poly(hydroxyalkanoate) from hydrolyzed linseed oil. J. Environ. Polymer Degradation 5, 153–158.
S510
Abstracts / Journal of Biotechnology 136S (2008) S506–S518
Shang, L.A., Fan, D.D., Kim, M.I., Choi, J., Chang, H.N., 2007. Modelling of poly(hydroxybutyrate) production by high cell density culture of Ralstonia eutropha. Biotechnol. Bioprocess Eng. 12, 417–423.
doi:10.1016/j.jbiotec.2008.07.632 V7-P-009 Displacement of endogenous iron in lipoxygenase by exogenous copper ions Yan Cai 2,∗ , Yong-Mei Xia 1,2 , Yun Fang 2 , Ya-Fen Su 2 1
State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China 2 School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China E-mail address: [email protected] (Y. Cai).
The interaction between exogenous and endogenous metal ions of metalloenzyme is very important in biocatalysis. Each molecule soybean lipoxygenase (LOX) contains one atom of endogenous Fe(II) (Cai et al., 2004), which is trapped in octahedral crystal cave and its activity can be accelerated by exogenous Cu2+ (André et al., 2004). However, the mechanism of the interaction remains unclear. According to Irving–Williams series theory and the fact that Cu2+ can also be trapped in octahedral crystal cave, we proposed that Cu2+ in solution trends to displace the endogenous Fe(II) in native LOX. To verify the hypothesis, one of the key technologies is to prove Cu2+ does displace Fe(II) instead of simply associating with the native LOX, qualitively and quantitively. Two indicators, p-carboxylantipyrylazo and 9-(4-carboxyphenyl)-2,3,7trihydroxyl-6-fluorone(CTF) (Li et al., 2004) were used to track the exchanging. After mixing LOX with copper sulfate solution, a missing of 0.53 mol/L Cu2+ in the solution was observed while an increase of 0.56 mol/L Fe2+ was detected in the solution meanwhile, which indicates that the exogenous Cu2+ displaced the endogenous Fe(II), and the replacement ratio of Fe(II) with Cu2+ was 3.48%.
Epoxide hydrolases from microbial sources have been increasingly recognized as highly versatile biocatalysts for the preparation of enantiopure epoxides and vicinal diols an important group of enantiomerically pure compounds to the chemical and pharmaceutical industries (Jaeger et al., 2001; Liu et al., 2007b). In our previous work, we have reported that a newly isolated Rhodococcus opacus ML-0004 producing the epoxide hydrolase. Also, a new gene encoding the epoxide hydrolase from R. opacus ML-0004 was cloned and expressed in Escherichia coli. The aim of this study is to further increase and optimize the epoxide hydrolase activity using the recombinant E. coli harboring epoxide hydrolase gene by response surface methodology. The maximal activity of epoxide hydrolase activity (5.5 U/mg) was predicted to occur when temperature = 30 ◦ C, inducer (IPTG) concentration = 0.5 mM, and duration of the induction period = 18 h. A repeat production of recombinant epoxide hydrolase by E. coli was carried out in a 5-L fermentor under the optimized conditions for the verification of optimization. The maximum epoxide hydrolase activity was 5.9 U/mg, which was significantly higher than that obtained under unoptimized conditions. References Jaeger, K.E., Eggert, T., Eipper, A., Reetz, M.T., 2001. Directed evolution and the creation of enantioselective biocatalysts. Appl. Microbiol. Biotechnol. 55, 519–530. Liu, Z.Q., Li, Y., Ping, L.F., Xu, Y.Y., Cui, F.J., Xue, Y.P., Zheng, Y.G., 2007a. Isolation and identification of a novel Rhodococcus sp. ML-0004 producing epoxide hydrolase and optimization of enzyme production. Process Biochem. 42, 889–894. Liu, Z.Q., Li, Y., Xu, Y.Y., Ping, L.F., Zheng, Y.G., 2007b. Cloning, sequencing, and expression of a novel epoxide hydrolase gene from Rhodococcus opacus in Escherichia coli and characterization of enzyme. Appl. Microbiol. Biotechnol. 74, 99–106. Steinreiber, A., Faber, K., 2001. Microbial epoxide hydroxylases for preparative biotransformations. Curr. Opin. Biotechnol. 12, 552–558. Weijers, C.A.G.M., de Bont, J.A.M., 1999. Epoxide hydrolases from yeasts and other sources: versatile tools in biocatalysis. J. Mol. Catal. B. 6, 199–214.
doi:10.1016/j.jbiotec.2008.07.634 V7-P-011
References André, K., Rayko, H., Ian, T.B., 2004. Silencing the jasmonate cascade: induced plant defenses and insect populations. Science 305, 665–668. Cai, K., Fang, Y., Xia, Y.M., Su, Y.F., 2004. Effect of exogenous iron on aerobic catalytic mechanism of soybean lipoxygenase. J. Mol. Catal. B: Enzym. 32, 21–26. Li, Z.J., Fan, Y., Liu, Z.Y., Tang, J., 2004. Spectrophotometric determination of iron(III)-dimethyldith-iocarbamate (ferbam) using 9-(4-carboxyphenyl)-2,3,7trihyoxyl-6-fluorone. Talanta 63, 647–651.
doi:10.1016/j.jbiotec.2008.07.633 V7-P-010 Optimization of the recombinant epoxide hydrolase activity from Escherichia coli using response surface methodology Zhiqiang Liu, Yuguo Zheng ∗ Institute of Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, PR China E-mail address: [email protected] (Y. Zheng). Epoxide hydrolases (EHs; EC 3.3.2.x) can hydrolyze an epoxide to its corresponding vicinal diol with the addition of a water molecule and without the need for any cofactors and prosthetic groups or metal ions for keeping their activities (Steinreiber and Faber, 2001). They were found in various mammals, insects, plants and microorganisms (Weijers and de Bont, 1999; Liu et al., 2007a).
Denitrification inhibiting sulfate reducing bacteria (SRB) activity in an anaerobic baffled reactor (ABR): Effect factors and mechanism analysis Zhaohan Zhang 1,2,∗ , Guangmin Liu 1 , Zhongxi Chen 3 , Zhiming Shu 3 , Yujie Feng 2 1 Department of Environmental Engineering, Harbin Engineering University, Harbin 150001, China 2 State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China 3 Daqing Oilfield Design and Research Institute, Daqing 163712, China
E-mail address: [email protected] (Z. Zhang). For controlling the equipment corrosion caused by the microbial production of hydrogen sulfide in oilfield land system, an experiment of denitrification inhibiting sulfate reduction was conducted in the continuous-flow ABR. Influential factors and running effect of denitrification inhibiting sulfate reduction were investigated. Batch experiments were conducted to study the inhibitory mechanisms. SO4 2− /NO3 − ratio and relative COD content were the most two important ecological factors affecting the denitrification inhibiting sulfate reduction. With the decreasing of SO4 2− /NO3 − ratio, inhibitory effect increased. The lower COD content benefited to increase the inhibitory effect. There were some effective action sections in the process of denitrification inhibiting sulfate reduction, and the effective inhibitory time was at 2.3 h–6.9 h. The
maximum enrichment ratio (9.86) and removal rate (98.63%) was obtained when the optimum conditions of gas flow-rate, pH, surfactant concentration, load volume were 0.05 m3 /h, 4.0, 0.16 g/l, 1.0 l, respectively. Comparing with the commonly used surfactantsodium dodecyl sulfate, DBAS would not leave Na+ in the aqueous solutions (Morgan and Wiesmann, 2002), thus a new idea was put forward for removing ions or salts by foam fractionation.
S509
Sun J, Xu, W.B., 2004. Particle Swarm Optimization with Particles Having Quantum Behavior. Proceedings 2004 Congress on Evolutionary Computation, pp. 325–331. Xu, W.B., Sun, J., 2004. Efficient Scheduling of Task Graphs to Multiprocessors Using a Simulated Annealing Algorithm. DCABES 2004 Proceedings, vol. 1, pp. 435–439.
doi:10.1016/j.jbiotec.2008.07.631 V7-P-008
References Bustos, G., Moldes, A.B., Alonso, J.L., 2004. Optimization of d-lactic acid production by Lactobacillus coryniformis using response surface methodology. Food Microbiol. 21, 143–148. Morgan, G., Wiesmann, U., 2002. Foam fractionation of surfactant-containing rinsing water. Chem. Ing. Technol. 74, 453–457. Yenidunya, M.D., 2006. Recovery of Zn(II), Mn(II) and Cu(II) in aqueous solutions by foam fractionation with sodium dodecyl sulphate in combination with chelating agents. Sep. Sci. Technol. 41, 1741–1756.
doi:10.1016/j.jbiotec.2008.07.630 V7-P-007 The optimization algorithm based biotechnology information Xiaohong Kong 1,∗ , Haizhen Mo 2 , Wei Zhang 1 , Mingfu Zhao 1 1
School of Electrical and Mechanical, Henan Institute of Science and Technology, Xinxiang, 453003, Henan province, China 2 School of Food Science, Henan Institute of Science and Technology, Xinxiang, 453003, China Intelligent optimization algorithms are a set of bionic algorithms to resolve complicated problems, which are well characterized by its self-organizing, self-learning, self-adaptive, implicit parallelism and guided search etc. These algorithms have been widely used to solve complex issues of engineering technology, nonlinear optimization, structural design, parallel computing, social science as well as many other fields. By employing the advantages of the intelligent optimization algorithms, this paper deals with the important problem of task matching and scheduling. In order to make full use of the potential power of network computing system, tasks matching and scheduling is one of the critical challenges in this filed and is also NP-hard. Solving the problem is of great significance to the development and application of high performance computing. Considering the universality of intelligent optimization algorithms against particularity of the specific issues, the proposed algorithm adjusts evolution strategies and design special operator. Based on common characteristics of the evolutionary algorithm, designing evolutionary algorithms for the scheduling problem are further investigated.
Production of polyhydroxyalkanoates from hydrolyzed corn oil by high cell density culture of Pseudomonas putida Longan Shang 1,2,∗ , Min Jiang 2,3 , Zhi Yun 2 , Ho Nam Chang 3 1
Ningbo Institute of Technology, Zhejiang University, NingBo 315100, China 2 Korea Advanced Institute of Science and Technology, Daejeon 305701, Republic of Korea 3 College of Pharmacy and Life Science, Nanjing University of Technology, Nanjing 210009, China E-mail address: [email protected] (L. Shang).
There is considerable industrial interest in Poly(3-hydroxyalkanoates) (PHAs), but their cost is a major issue. To make PHAs production more economical, some researchers have tried to produce PHAs from inexpensive carbon sources such as plant oils. However their productivities were so low that they were impossible to be used for carrying out mass production. There were some flask cultures that had showed Pseudomonas putida being able to produce PHAs from hydrolyzed palm oil and hydrolyzed linseed oil (Annuar et al., 2007; Casini et al., 1997). Corn oil is a rich renewable source; however, there is no report on how to use corn oil to produce PHAs. This paper demonstrated that the medium-chain-length PHAs could be made effectively from the corn oil hydrolysate, an inexpensive and renewable carbon source, by high cell density cultures of P. putida under a phosphate limitation. Corn oil was hydrolyzed using lipase from Candida rugosa (Sigma 724 U/mg). The dissolved oxygen concentration was used as an online signal for feeding corn oil hydrolysate. Other detailed information on fermentation and analysis methods could be found in the previous work (Shang et al., 2007). The cell growth, MCL–PHAs accumulation and feeding strategies of corn oil hydrolysate in the cultures of P. putida were investigated in 5 L and 30 L fermentors respectively. In the 30-L scale fermentation, the final cell concentration and MCL–PHAs concentrations reached 103 and 28 g/L, which represents a MCL–PHAs productivity of 0.61 g/L h. It was confirmed by the NMR spectrum that this MCL–PHAs from corn oil hydrolysate contained 4 saturated and 3 unsaturated monomers with a chain length of 6–14 carbon atoms.
Keywords: Biotechnology; Intelligent optimization algorithms; Ant colony optimization; Evolutionary algorithms Acknowledgements References ´ T., Crainic, T.G., 2006. Benchmark-Problem instances for static task Davidovic, scheduling of task graphs with communication delays on homogeneous multiprocessor systems. Comput. OR 33 (8), 2155–2177. Kong, X.H., Xu, W.B., Liu, J., 2006a. A Permutation-Based Differential Evolution Algorithm Incorporating Simulated Annealing for Multiprocessor Scheduling with Communication Delays. International Conference on Computational Science, LNCS 3991. Kong, X.H., Sun. J., Xu, W.B., 2006b. Particle Swarm Algorithm for Tasks Scheduling in Distributed Heterogeneous System. Sixth International Conference on Intelligent System Design and Applications, p. 2. Kong, X.H., Sun, J., Xu, W.B., 2006c. Parallel Ant Colony Algorithm for Multiprocessor Scheduling with Communication Delays. 2006 International Symposium and Distributed Computing and Applications to Electron, Engineering and Science, p. 1.
This work was funded by the Ningbo Natural Science Foundation (2006A610043), and the Science and Technology Department of Zhejiang province (2007R10020).
References Annuar, M., Suffian, M., Tna, I.K.P., Ibrahim, S., Ramachandran, K.B., 2007. Production of medium-chain length poly(3-hydroxyalkanoates) from crude fatty acids mixture by Pseudomonas putida. Food Bioprod. Process. 85 (2), 104–109. Casini, E., de Rijk, T.C., de Waard, P., Eggink, G., 1997. Synthesis of poly(hydroxyalkanoate) from hydrolyzed linseed oil. J. Environ. Polymer Degradation 5, 153–158.
S510
Abstracts / Journal of Biotechnology 136S (2008) S506–S518
Shang, L.A., Fan, D.D., Kim, M.I., Choi, J., Chang, H.N., 2007. Modelling of poly(hydroxybutyrate) production by high cell density culture of Ralstonia eutropha. Biotechnol. Bioprocess Eng. 12, 417–423.
doi:10.1016/j.jbiotec.2008.07.632 V7-P-009 Displacement of endogenous iron in lipoxygenase by exogenous copper ions Yan Cai 2,∗ , Yong-Mei Xia 1,2 , Yun Fang 2 , Ya-Fen Su 2 1
State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China 2 School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China E-mail address: [email protected] (Y. Cai).
The interaction between exogenous and endogenous metal ions of metalloenzyme is very important in biocatalysis. Each molecule soybean lipoxygenase (LOX) contains one atom of endogenous Fe(II) (Cai et al., 2004), which is trapped in octahedral crystal cave and its activity can be accelerated by exogenous Cu2+ (André et al., 2004). However, the mechanism of the interaction remains unclear. According to Irving–Williams series theory and the fact that Cu2+ can also be trapped in octahedral crystal cave, we proposed that Cu2+ in solution trends to displace the endogenous Fe(II) in native LOX. To verify the hypothesis, one of the key technologies is to prove Cu2+ does displace Fe(II) instead of simply associating with the native LOX, qualitively and quantitively. Two indicators, p-carboxylantipyrylazo and 9-(4-carboxyphenyl)-2,3,7trihydroxyl-6-fluorone(CTF) (Li et al., 2004) were used to track the exchanging. After mixing LOX with copper sulfate solution, a missing of 0.53 mol/L Cu2+ in the solution was observed while an increase of 0.56 mol/L Fe2+ was detected in the solution meanwhile, which indicates that the exogenous Cu2+ displaced the endogenous Fe(II), and the replacement ratio of Fe(II) with Cu2+ was 3.48%.
Epoxide hydrolases from microbial sources have been increasingly recognized as highly versatile biocatalysts for the preparation of enantiopure epoxides and vicinal diols an important group of enantiomerically pure compounds to the chemical and pharmaceutical industries (Jaeger et al., 2001; Liu et al., 2007b). In our previous work, we have reported that a newly isolated Rhodococcus opacus ML-0004 producing the epoxide hydrolase. Also, a new gene encoding the epoxide hydrolase from R. opacus ML-0004 was cloned and expressed in Escherichia coli. The aim of this study is to further increase and optimize the epoxide hydrolase activity using the recombinant E. coli harboring epoxide hydrolase gene by response surface methodology. The maximal activity of epoxide hydrolase activity (5.5 U/mg) was predicted to occur when temperature = 30 ◦ C, inducer (IPTG) concentration = 0.5 mM, and duration of the induction period = 18 h. A repeat production of recombinant epoxide hydrolase by E. coli was carried out in a 5-L fermentor under the optimized conditions for the verification of optimization. The maximum epoxide hydrolase activity was 5.9 U/mg, which was significantly higher than that obtained under unoptimized conditions. References Jaeger, K.E., Eggert, T., Eipper, A., Reetz, M.T., 2001. Directed evolution and the creation of enantioselective biocatalysts. Appl. Microbiol. Biotechnol. 55, 519–530. Liu, Z.Q., Li, Y., Ping, L.F., Xu, Y.Y., Cui, F.J., Xue, Y.P., Zheng, Y.G., 2007a. Isolation and identification of a novel Rhodococcus sp. ML-0004 producing epoxide hydrolase and optimization of enzyme production. Process Biochem. 42, 889–894. Liu, Z.Q., Li, Y., Xu, Y.Y., Ping, L.F., Zheng, Y.G., 2007b. Cloning, sequencing, and expression of a novel epoxide hydrolase gene from Rhodococcus opacus in Escherichia coli and characterization of enzyme. Appl. Microbiol. Biotechnol. 74, 99–106. Steinreiber, A., Faber, K., 2001. Microbial epoxide hydroxylases for preparative biotransformations. Curr. Opin. Biotechnol. 12, 552–558. Weijers, C.A.G.M., de Bont, J.A.M., 1999. Epoxide hydrolases from yeasts and other sources: versatile tools in biocatalysis. J. Mol. Catal. B. 6, 199–214.
doi:10.1016/j.jbiotec.2008.07.634 V7-P-011
References André, K., Rayko, H., Ian, T.B., 2004. Silencing the jasmonate cascade: induced plant defenses and insect populations. Science 305, 665–668. Cai, K., Fang, Y., Xia, Y.M., Su, Y.F., 2004. Effect of exogenous iron on aerobic catalytic mechanism of soybean lipoxygenase. J. Mol. Catal. B: Enzym. 32, 21–26. Li, Z.J., Fan, Y., Liu, Z.Y., Tang, J., 2004. Spectrophotometric determination of iron(III)-dimethyldith-iocarbamate (ferbam) using 9-(4-carboxyphenyl)-2,3,7trihyoxyl-6-fluorone. Talanta 63, 647–651.
doi:10.1016/j.jbiotec.2008.07.633 V7-P-010 Optimization of the recombinant epoxide hydrolase activity from Escherichia coli using response surface methodology Zhiqiang Liu, Yuguo Zheng ∗ Institute of Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, PR China E-mail address: [email protected] (Y. Zheng). Epoxide hydrolases (EHs; EC 3.3.2.x) can hydrolyze an epoxide to its corresponding vicinal diol with the addition of a water molecule and without the need for any cofactors and prosthetic groups or metal ions for keeping their activities (Steinreiber and Faber, 2001). They were found in various mammals, insects, plants and microorganisms (Weijers and de Bont, 1999; Liu et al., 2007a).
Denitrification inhibiting sulfate reducing bacteria (SRB) activity in an anaerobic baffled reactor (ABR): Effect factors and mechanism analysis Zhaohan Zhang 1,2,∗ , Guangmin Liu 1 , Zhongxi Chen 3 , Zhiming Shu 3 , Yujie Feng 2 1 Department of Environmental Engineering, Harbin Engineering University, Harbin 150001, China 2 State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China 3 Daqing Oilfield Design and Research Institute, Daqing 163712, China
E-mail address: [email protected] (Z. Zhang). For controlling the equipment corrosion caused by the microbial production of hydrogen sulfide in oilfield land system, an experiment of denitrification inhibiting sulfate reduction was conducted in the continuous-flow ABR. Influential factors and running effect of denitrification inhibiting sulfate reduction were investigated. Batch experiments were conducted to study the inhibitory mechanisms. SO4 2− /NO3 − ratio and relative COD content were the most two important ecological factors affecting the denitrification inhibiting sulfate reduction. With the decreasing of SO4 2− /NO3 − ratio, inhibitory effect increased. The lower COD content benefited to increase the inhibitory effect. There were some effective action sections in the process of denitrification inhibiting sulfate reduction, and the effective inhibitory time was at 2.3 h–6.9 h. The