- Email: [email protected]
Microorganism strain improvement for biofuels: Desired traits obtainable by engineering the global transcription machinery
S10
Abstracts / Journal of Biotechnology 136S (2008) S6–S15
tured shrimp. IgY is a promising alternative to antibiotics for passive immunotherapy application, however, its application is limited by its sensitivity to gastric conditions. Therefore, it is highly necessary to develop an effective delivery system to protect orally administered IgY from the harsh gastrointestinal environment enroute to the infection site in the intestine. The microencapsulation technique enables a larger proportion of IgY to remain bioactive in simulated gastro-intestinal tract environment, providing a more effective delivery of specific IgY (Kovacs-Nolan and Mine, 2005; Li et al., 2007). This review presents an overview of potential immunotherapy with specific IgY for the prevention and treatment of land and aquatic animal diseases and speculates on the future of IgY technology. References Carlander, D., Kollberg, H., Wejaker, P.E., Larsson, A., 2000. Peroral immunotherapy with yolk antibodies for the prevention and treatment of enteric infections. Immunol. Res. 21, 1–6. Gutierrez, M.A., Miyazaki, T., Hatta, H., Kim, M., 1993. Protective properties of egg yolk IgY containing anti-Edwardsiella tarda antibody against paracolo disease in the Japanese eel, Anguilla japonica Temminck & Schlegel. J. Fish Dis. 16, 113–122. Ikemori, Y., Kuroki, M., Peralta, R.C., Yokoyama, H., Kodama, Y., 1992. Protection of neonatal calves against fatal enteric colibacillosis by administration of egg yolk powder from hens immunized with K99-piliated enterotoxigenic Escherichia coli. Am. J. Vet. Res. 53, 2005–2008. Ikemori, Y., Ohta, M., Umeda, K., Icatlo, F.C., Kuroki, M., Yokoyama, H., Kodama, Y., 1997. Passive protection of neonatal calves against bovine coronavirus-induced diarrhea by administration of egg yolk or colostrum antibody powder. Vet. Microbiol. 58, 105–111. Kovacs-Nolan, J., Mine, Y., 2005. Microencapsulation for the gastric passage and controlled intestinal release of immunoglobulin Y. J. Immunol. Methods 296, 199–209. Lee, S.B., Mine, Y., Stevenson, R.M.W., 2000. Effects of hen egg yolk immunoglobulin in passive protection of rainbow trout against Yersinia ruckeri. J. Agric. Food Chem. 48, 110–115. Li, X.Y., Jin, L.J., McAllister, T.A., Stanford, K., Xu, J.Y., Lu, Y.N., Zhen, Y.H., Sun, Y.X., Xu, Y.P., 2007. Chitosan–alginate microcapsules for oral delivery of egg yolk immunoglobulin (IgY). J. Agric. Food Chem. 55, 2911–2917. Marquardt, R.R., Jin, L.Z., Kim, J.W., Fang, L., Frohlich, A.A., Baidoo, S.K., 1999. Passive protective effect of egg-yolk antibodies against enterotoxigenic Escherichia coli K88+ infection in neonatal and early-weaned piglets. FEMS Immunol. Med. Microbiol. 23, 283–288. O’Farrely, C., Branton, D., Wanke, C.A., 1992. Oral ingestion of egg yolk immunoglobulins from hens immunized with an enterotoxigenic Escherichia coli strain prevents diarrhea in rabbits challenged with the same strain. Infect. Immun. 60, 2593–2597. Rahimi, S., Shiraz, Z.M., Salehi, T.Z., Torshizi, M.A.K., Grimes, J.L., 2007a. Prevention of Salmonella infection in poultry by specific egg-derived antibody. Int. J. Poultry Sci. 6, 230–235. Rahimi, S., Salehifar, E., Ghorashi, S.A., Grimes, J.L., Torshizi, M.A.K., 2007b. The effect of egg-derived antibody on prevention of avian influenza subtype H9N2 in layer chicken. Int. J. Poultry Sci. 6, 207–210. Yokoyama, H., Peralta, R.C., Diaz, R., Sendo, S., Ikemori, Y., Kodama, Y., 1992a. Passive protective effect of chicken egg yolk immunoglobulins against experimental enterotoxigenic Escherichia coli infection in neonatal piglets. Infect. Immun. 60, 998–1007. Yokoyama, H., Peralta, R.C., Umeda, K., Hashi, T., Icatlo, F.C., Kuroki, M., Ikemori, Y., Kodama, Y., 1992b. Prevention of fatal salmonellosis in neonatal calves, using orally administered chicken egg yolk Salmonella-specific antibodies. Am. J. Vet. Res. 59, 416–420. Zhen, Y.H., Jin, L.J., Guo, J., Li, X.Y., Li, Z., Fang, R., Xu, Y.P. Charcterization of specific egg yolk immunoglobulin (IgY) against mastitis-causing Staphylococcus aureus. J. Appl. Microbiol., in press.
doi:10.1016/j.jbiotec.2008.07.1800
IL-063 New techniques reveal new mechanisms—The role of aerobic anoxygenic phototrophs in carbon cycling in the ocean Nianzhi Jiao National Key Laboratory for Marine Environmental Sciences, Xiamen 361005, PR China E-mail address: [email protected]. Aerobic anoxygenic phototrophic bacteria (AAPB) are a group of heterotrophic bacteria that can utilize light for supplemental energy. Field survey in the global oceans showed that AAPB are more abundant in eutrophic waters than in oligotrophic oceans, which is against the theoretical speculation that AAPB should be more competitive over other bacteria when dissolved organic carbon (DOC) are sparse. Statistic analysis showed that AAPB were closely associated with phytoplankton, this fact was verified by in situ incubation experiments. Contrasting to the fast growth of AAPB in the field, AAPB lab cultures grow very slowly under lab conditions, probably due to no DOC supplies from phytoplankton. This is verified by the selective use of carbon source by AAPB as seen through Biolog bioassay (95 carbon species provided) and membrane potential observations by flow cytometry. Therefore, AAPB would serve as an effective “Microbial Pump” that takes up phytoplankton DOC and releases refractory DOC (RDOC) into the water. Such process together with other processes forming RDOC are helpful for the understanding of RDOC formation and consequences regarding carbon sequestration in the ocean. Further more, the contribution of AAPB through utilization of light energy to carbon flow in the surface ocean is estimated based on the field observations and experimental conversion factors, and a new model of carbon cycling in the surface ocean is established. doi:10.1016/j.jbiotec.2008.07.1801 IL-075 Microorganism strain improvement for biofuels: Desired traits obtainable by engineering the global transcription machinery Ribo Huang 1,∗ , Qingyan Wang 1 , Dengfeng Yang 1 , Wenpu Zuo 1 , Yutuo Wei 2 , Liqin Du 2 1
Guangxi Academy of Sciences, 98 Daling Road, Nanning, Guangxi 530007, China 2 College of Life Science and Biotechnology, Guangxi University, 100 University Road, Nanning, Guangxi 530004, China E-mail address: [email protected] (R. Huang).
In the field of current biotechnology, many desirable phenotypes of industrial microorganisms are controlled or regulated by multiple genes (Alper et al., 2006). Among these traits, ethanol tolerance in Saccharomyces cerevisiae could be influenced by up to 251 genes since the knockouts of these genes could lead to decreased ethanol tolerance (Hu et al., 2007). Works on 1-butanol tolerance has been also shown that so far at least as many as 16 genes may be involved in this phenotype (Borden and Papoutsakis, 2007). Currently, engineering on the global transcription machinery is being carried out in our laboratory for the increases of ethanol tolerance in S. cerevisiae and 1-butanol tolerance in Clostridium acetobutylicum ATCC 824. Started with a locally isolated novel S. cerevisiae strain (Patent pending, 2008), which can grow on 31% sugar and produce up to 18.5% (v/v) ethanol, we found that a considerable improvement in the tolerance can be achieved. Using the
Abstracts / Journal of Biotechnology 136S (2008) S6–S15
same strategy, 1-butanol tolerance/production can be increased from 1.4% to nearly 2.0%, which shows a great potential in industrial applications.
S11
Takeo, M., Yasukawa, T., Abe, Y., Niihara, S., Maeda, Y., Negoro, S., 2003. Cloning and characterization of a 4-nitrophenol hydroxylase gene cluster from Rhodococcus sp. PN1. J. Biosci. Bioeng. 95, 139–145.
doi:10.1016/j.jbiotec.2008.07.1803 References Alper, H., Moxley, J., Nevoigt, E., Fink, R., Stephanopoulos, G., 2006. Engineering yeast transcription machinery for improved ethanol tolerance and production. Science 314, 1565–1568. Borden, J.R., Papoutsakis, E.T., 2007. Dynamics of genomic-library enrichment and identification solvent tolerance genes for Clostridium acetobutylicum. Appl. Environ. Microbiol. 73, 3061–3068. Hu, X.H., Wang, M.H., Tan, T., Li, J.R., Yang, Y., Leach, L., Zhang, R.M., Luo, Z.H., 2007. Genetic dissection of ethanol tolerance in the budding yeast Sccharomyces cerevisiae. Genetics 175, 1479–1487. Patent pending.
IL-095 Interaction of phytopromotional fungi and plant cells on synthesis of plant-derived metabolites V.S. Bisaria ∗ , A. Baldi, V. Kumar, N. Gupta, A. Jain, S. Farkya, A.K. Srivastava Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology-Delhi, New Delhi 110016, India E-mail address: [email protected] (V.S. Bisaria).
doi:10.1016/j.jbiotec.2008.07.1802 IL-090 Bacterial metabolisms of soil contaminants, nitrophenols Masahiro Takeo 1,∗ , Dai-ichiro Kato 1 , Seiji Negoro 1 , Rakesh K. Jain 2 1 Department of Materials Science and Chemistry, Graduate School of Engineering, University of Hyogo, Himeji, Japan 2 Institute of Microbial Technology, Chandigarh, India
E-mail address: [email protected] (M. Takeo). Nitrophenols are produced in large quantities as building blocks for synthesis of chemical products. Through the use of such chemical products, they contaminate soils and aquatic environments. For instance, p-nitrophenol (PNP) is frequently detected in agricultural soils as a metabolite of organophosphorus pesticides parathion and methylparathion. 2,4-Dinitrophenol (2,4-DNP) herbicides such as DNOC and Dinoseb also directly contaminate agricultural soils. In addition, 2,4,6-trinitrophenol (picric acid), which has been produced as an explosive, pollutes soils in/around chemical plants and military facilities. Generally, these compounds are very toxic, and even mutagenic and carcinogenic once they are bioconverted into the corresponding aromatic amines under anaerobic environments. Bioremediation is one of choices to remove these risky compounds from contaminated soils inexpensively. To carry out bioremediation efficiently, basic understanding of the biodegradation mechanisms is indispensable. In this study, we introduce bacterial metabolisms of nitrophenols, mainly PNP degradation by Rhodococcus sp. PN1. This strain can assimilate PNP and 2,4DNP as a sole carbon and nitrogen source and also picric acid as a nitrogen source. For the PNP degradation, PN1 has two kinds of gene clusters, nphRA1A2 (Takeo et al., 2003) and npsRA2A1B, each including a different two-component PNP monooxygenase gene. In contrast, for 2,4-DNP and picric acid degradation, it also has the npdGI gene cluster encoding an NADPH-dependent F420 reductase and a hydride transferase (Heiss et al., 2003). Herein, we show the characteristics of the enzymes catalyzing the initial degradation of nitrophenols and the regulatory mechanisms of their gene expression. Keywords: Nitrophenol degradation; Rhodococcus; Gene regulation; Monooxygenase; Bioremediation References Heiss, G., Trachtmann, N., Abe, Y., Takeo, M., Knackmuss, H.-J., 2003. Homologous npdGI genes in 2,4-dinitrophenol and 4-nitrophenol degrading Rhodococcus spp. Appl. Environ. Microbiol. 69, 2748–2754.
Piriformospora indica and Sebacina vermifera are arbuscular mycorrhiza (AM) like-fungi which have a broad and diverse spectrum, exert promotional effects on host plants and act as a tool for biological hardening of micropropagated plants. But the most important advantage of these two fungi over AM fungi is that they are facultative symbionts and can be easily cultivated axenically (Varma et al., 1999). Linum album is a perennial plant. The main lignan in L. album is podophyllotoxin, which is used for the semisynthetic production of the antitumour agents, etoposide, etopophos and teniposide. Lignans are defence molecules produced by plants in response to any pathogenic attack or under stress conditions by elicitation (Farkya et al., 2004). To investigate phytopromotional effect and stimulation of lignan biosynthesis, the effect of culture filtrates of P. indica and S. vermifera on growth of L. album cells in suspension culture and on production of podophyllotoxin (PT) and 5-methoxypodophyllotoxin (5-MPT) was studied. For this purpose, different volumes of culture filtrate of P. indica/S. vermifera were added to suspension culture of L. album during different phases of growth. The culture filtrates of both the fungi had a positive effect on product formation. Further, to investigate if the two fungi have some plant growth promoting activity along with production of elicitors, which could activate biosynthetic pathway of PT production, both the fungi were individually co-cultivated with L. album in suspension cultures for different time periods and at different levels of fungal inoculum (Baldi et al., 2008). The PT and 5-MPT content in both the cases was found to be significantly enhanced on co-culturing with the plant cells. The activity of phenylalanine ammonia lyase was observed to be related to the lignan accumulation indicating its role as the key enzyme of the phenylpropanoid pathway. The study resulted in lignan accumulation of 740 mg/L of the culture broth with a very high productivity of 52 mg/(L d). References Baldi, A., Jain, A., Gupta, N., Srivastava, A.K., Bisaria, V.S., 2008. Co-culture of arbuscular mycorrhiza-like fungi (Piriformospora indica and Sebacina vermifera) with plant cells of Linum album for enhanced production of podophyllotoxins: a first report. Biotechnol. Lett., PMID: 18427926. Farkya, S., Bisaria, V.S., Srivastava, A.K., 2004. Biotechnological aspects of the production of anti-cancer drug podophyllotoxin. Appl. Microbiol. Biotechnol. 65, 504–519. Varma, A., Sudha, S., Franken, P., 1999. Piriformospora indica—a cultivable plant growth promoting root endophyte with similarities to arbuscular mycorrhizal fungi. Appl. Environ. Microbiol. 65, 2741–2744.
doi:10.1016/j.jbiotec.2008.07.1804
Abstracts / Journal of Biotechnology 136S (2008) S6–S15
tured shrimp. IgY is a promising alternative to antibiotics for passive immunotherapy application, however, its application is limited by its sensitivity to gastric conditions. Therefore, it is highly necessary to develop an effective delivery system to protect orally administered IgY from the harsh gastrointestinal environment enroute to the infection site in the intestine. The microencapsulation technique enables a larger proportion of IgY to remain bioactive in simulated gastro-intestinal tract environment, providing a more effective delivery of specific IgY (Kovacs-Nolan and Mine, 2005; Li et al., 2007). This review presents an overview of potential immunotherapy with specific IgY for the prevention and treatment of land and aquatic animal diseases and speculates on the future of IgY technology. References Carlander, D., Kollberg, H., Wejaker, P.E., Larsson, A., 2000. Peroral immunotherapy with yolk antibodies for the prevention and treatment of enteric infections. Immunol. Res. 21, 1–6. Gutierrez, M.A., Miyazaki, T., Hatta, H., Kim, M., 1993. Protective properties of egg yolk IgY containing anti-Edwardsiella tarda antibody against paracolo disease in the Japanese eel, Anguilla japonica Temminck & Schlegel. J. Fish Dis. 16, 113–122. Ikemori, Y., Kuroki, M., Peralta, R.C., Yokoyama, H., Kodama, Y., 1992. Protection of neonatal calves against fatal enteric colibacillosis by administration of egg yolk powder from hens immunized with K99-piliated enterotoxigenic Escherichia coli. Am. J. Vet. Res. 53, 2005–2008. Ikemori, Y., Ohta, M., Umeda, K., Icatlo, F.C., Kuroki, M., Yokoyama, H., Kodama, Y., 1997. Passive protection of neonatal calves against bovine coronavirus-induced diarrhea by administration of egg yolk or colostrum antibody powder. Vet. Microbiol. 58, 105–111. Kovacs-Nolan, J., Mine, Y., 2005. Microencapsulation for the gastric passage and controlled intestinal release of immunoglobulin Y. J. Immunol. Methods 296, 199–209. Lee, S.B., Mine, Y., Stevenson, R.M.W., 2000. Effects of hen egg yolk immunoglobulin in passive protection of rainbow trout against Yersinia ruckeri. J. Agric. Food Chem. 48, 110–115. Li, X.Y., Jin, L.J., McAllister, T.A., Stanford, K., Xu, J.Y., Lu, Y.N., Zhen, Y.H., Sun, Y.X., Xu, Y.P., 2007. Chitosan–alginate microcapsules for oral delivery of egg yolk immunoglobulin (IgY). J. Agric. Food Chem. 55, 2911–2917. Marquardt, R.R., Jin, L.Z., Kim, J.W., Fang, L., Frohlich, A.A., Baidoo, S.K., 1999. Passive protective effect of egg-yolk antibodies against enterotoxigenic Escherichia coli K88+ infection in neonatal and early-weaned piglets. FEMS Immunol. Med. Microbiol. 23, 283–288. O’Farrely, C., Branton, D., Wanke, C.A., 1992. Oral ingestion of egg yolk immunoglobulins from hens immunized with an enterotoxigenic Escherichia coli strain prevents diarrhea in rabbits challenged with the same strain. Infect. Immun. 60, 2593–2597. Rahimi, S., Shiraz, Z.M., Salehi, T.Z., Torshizi, M.A.K., Grimes, J.L., 2007a. Prevention of Salmonella infection in poultry by specific egg-derived antibody. Int. J. Poultry Sci. 6, 230–235. Rahimi, S., Salehifar, E., Ghorashi, S.A., Grimes, J.L., Torshizi, M.A.K., 2007b. The effect of egg-derived antibody on prevention of avian influenza subtype H9N2 in layer chicken. Int. J. Poultry Sci. 6, 207–210. Yokoyama, H., Peralta, R.C., Diaz, R., Sendo, S., Ikemori, Y., Kodama, Y., 1992a. Passive protective effect of chicken egg yolk immunoglobulins against experimental enterotoxigenic Escherichia coli infection in neonatal piglets. Infect. Immun. 60, 998–1007. Yokoyama, H., Peralta, R.C., Umeda, K., Hashi, T., Icatlo, F.C., Kuroki, M., Ikemori, Y., Kodama, Y., 1992b. Prevention of fatal salmonellosis in neonatal calves, using orally administered chicken egg yolk Salmonella-specific antibodies. Am. J. Vet. Res. 59, 416–420. Zhen, Y.H., Jin, L.J., Guo, J., Li, X.Y., Li, Z., Fang, R., Xu, Y.P. Charcterization of specific egg yolk immunoglobulin (IgY) against mastitis-causing Staphylococcus aureus. J. Appl. Microbiol., in press.
doi:10.1016/j.jbiotec.2008.07.1800
IL-063 New techniques reveal new mechanisms—The role of aerobic anoxygenic phototrophs in carbon cycling in the ocean Nianzhi Jiao National Key Laboratory for Marine Environmental Sciences, Xiamen 361005, PR China E-mail address: [email protected]. Aerobic anoxygenic phototrophic bacteria (AAPB) are a group of heterotrophic bacteria that can utilize light for supplemental energy. Field survey in the global oceans showed that AAPB are more abundant in eutrophic waters than in oligotrophic oceans, which is against the theoretical speculation that AAPB should be more competitive over other bacteria when dissolved organic carbon (DOC) are sparse. Statistic analysis showed that AAPB were closely associated with phytoplankton, this fact was verified by in situ incubation experiments. Contrasting to the fast growth of AAPB in the field, AAPB lab cultures grow very slowly under lab conditions, probably due to no DOC supplies from phytoplankton. This is verified by the selective use of carbon source by AAPB as seen through Biolog bioassay (95 carbon species provided) and membrane potential observations by flow cytometry. Therefore, AAPB would serve as an effective “Microbial Pump” that takes up phytoplankton DOC and releases refractory DOC (RDOC) into the water. Such process together with other processes forming RDOC are helpful for the understanding of RDOC formation and consequences regarding carbon sequestration in the ocean. Further more, the contribution of AAPB through utilization of light energy to carbon flow in the surface ocean is estimated based on the field observations and experimental conversion factors, and a new model of carbon cycling in the surface ocean is established. doi:10.1016/j.jbiotec.2008.07.1801 IL-075 Microorganism strain improvement for biofuels: Desired traits obtainable by engineering the global transcription machinery Ribo Huang 1,∗ , Qingyan Wang 1 , Dengfeng Yang 1 , Wenpu Zuo 1 , Yutuo Wei 2 , Liqin Du 2 1
Guangxi Academy of Sciences, 98 Daling Road, Nanning, Guangxi 530007, China 2 College of Life Science and Biotechnology, Guangxi University, 100 University Road, Nanning, Guangxi 530004, China E-mail address: [email protected] (R. Huang).
In the field of current biotechnology, many desirable phenotypes of industrial microorganisms are controlled or regulated by multiple genes (Alper et al., 2006). Among these traits, ethanol tolerance in Saccharomyces cerevisiae could be influenced by up to 251 genes since the knockouts of these genes could lead to decreased ethanol tolerance (Hu et al., 2007). Works on 1-butanol tolerance has been also shown that so far at least as many as 16 genes may be involved in this phenotype (Borden and Papoutsakis, 2007). Currently, engineering on the global transcription machinery is being carried out in our laboratory for the increases of ethanol tolerance in S. cerevisiae and 1-butanol tolerance in Clostridium acetobutylicum ATCC 824. Started with a locally isolated novel S. cerevisiae strain (Patent pending, 2008), which can grow on 31% sugar and produce up to 18.5% (v/v) ethanol, we found that a considerable improvement in the tolerance can be achieved. Using the
Abstracts / Journal of Biotechnology 136S (2008) S6–S15
same strategy, 1-butanol tolerance/production can be increased from 1.4% to nearly 2.0%, which shows a great potential in industrial applications.
S11
Takeo, M., Yasukawa, T., Abe, Y., Niihara, S., Maeda, Y., Negoro, S., 2003. Cloning and characterization of a 4-nitrophenol hydroxylase gene cluster from Rhodococcus sp. PN1. J. Biosci. Bioeng. 95, 139–145.
doi:10.1016/j.jbiotec.2008.07.1803 References Alper, H., Moxley, J., Nevoigt, E., Fink, R., Stephanopoulos, G., 2006. Engineering yeast transcription machinery for improved ethanol tolerance and production. Science 314, 1565–1568. Borden, J.R., Papoutsakis, E.T., 2007. Dynamics of genomic-library enrichment and identification solvent tolerance genes for Clostridium acetobutylicum. Appl. Environ. Microbiol. 73, 3061–3068. Hu, X.H., Wang, M.H., Tan, T., Li, J.R., Yang, Y., Leach, L., Zhang, R.M., Luo, Z.H., 2007. Genetic dissection of ethanol tolerance in the budding yeast Sccharomyces cerevisiae. Genetics 175, 1479–1487. Patent pending.
IL-095 Interaction of phytopromotional fungi and plant cells on synthesis of plant-derived metabolites V.S. Bisaria ∗ , A. Baldi, V. Kumar, N. Gupta, A. Jain, S. Farkya, A.K. Srivastava Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology-Delhi, New Delhi 110016, India E-mail address: [email protected] (V.S. Bisaria).
doi:10.1016/j.jbiotec.2008.07.1802 IL-090 Bacterial metabolisms of soil contaminants, nitrophenols Masahiro Takeo 1,∗ , Dai-ichiro Kato 1 , Seiji Negoro 1 , Rakesh K. Jain 2 1 Department of Materials Science and Chemistry, Graduate School of Engineering, University of Hyogo, Himeji, Japan 2 Institute of Microbial Technology, Chandigarh, India
E-mail address: [email protected] (M. Takeo). Nitrophenols are produced in large quantities as building blocks for synthesis of chemical products. Through the use of such chemical products, they contaminate soils and aquatic environments. For instance, p-nitrophenol (PNP) is frequently detected in agricultural soils as a metabolite of organophosphorus pesticides parathion and methylparathion. 2,4-Dinitrophenol (2,4-DNP) herbicides such as DNOC and Dinoseb also directly contaminate agricultural soils. In addition, 2,4,6-trinitrophenol (picric acid), which has been produced as an explosive, pollutes soils in/around chemical plants and military facilities. Generally, these compounds are very toxic, and even mutagenic and carcinogenic once they are bioconverted into the corresponding aromatic amines under anaerobic environments. Bioremediation is one of choices to remove these risky compounds from contaminated soils inexpensively. To carry out bioremediation efficiently, basic understanding of the biodegradation mechanisms is indispensable. In this study, we introduce bacterial metabolisms of nitrophenols, mainly PNP degradation by Rhodococcus sp. PN1. This strain can assimilate PNP and 2,4DNP as a sole carbon and nitrogen source and also picric acid as a nitrogen source. For the PNP degradation, PN1 has two kinds of gene clusters, nphRA1A2 (Takeo et al., 2003) and npsRA2A1B, each including a different two-component PNP monooxygenase gene. In contrast, for 2,4-DNP and picric acid degradation, it also has the npdGI gene cluster encoding an NADPH-dependent F420 reductase and a hydride transferase (Heiss et al., 2003). Herein, we show the characteristics of the enzymes catalyzing the initial degradation of nitrophenols and the regulatory mechanisms of their gene expression. Keywords: Nitrophenol degradation; Rhodococcus; Gene regulation; Monooxygenase; Bioremediation References Heiss, G., Trachtmann, N., Abe, Y., Takeo, M., Knackmuss, H.-J., 2003. Homologous npdGI genes in 2,4-dinitrophenol and 4-nitrophenol degrading Rhodococcus spp. Appl. Environ. Microbiol. 69, 2748–2754.
Piriformospora indica and Sebacina vermifera are arbuscular mycorrhiza (AM) like-fungi which have a broad and diverse spectrum, exert promotional effects on host plants and act as a tool for biological hardening of micropropagated plants. But the most important advantage of these two fungi over AM fungi is that they are facultative symbionts and can be easily cultivated axenically (Varma et al., 1999). Linum album is a perennial plant. The main lignan in L. album is podophyllotoxin, which is used for the semisynthetic production of the antitumour agents, etoposide, etopophos and teniposide. Lignans are defence molecules produced by plants in response to any pathogenic attack or under stress conditions by elicitation (Farkya et al., 2004). To investigate phytopromotional effect and stimulation of lignan biosynthesis, the effect of culture filtrates of P. indica and S. vermifera on growth of L. album cells in suspension culture and on production of podophyllotoxin (PT) and 5-methoxypodophyllotoxin (5-MPT) was studied. For this purpose, different volumes of culture filtrate of P. indica/S. vermifera were added to suspension culture of L. album during different phases of growth. The culture filtrates of both the fungi had a positive effect on product formation. Further, to investigate if the two fungi have some plant growth promoting activity along with production of elicitors, which could activate biosynthetic pathway of PT production, both the fungi were individually co-cultivated with L. album in suspension cultures for different time periods and at different levels of fungal inoculum (Baldi et al., 2008). The PT and 5-MPT content in both the cases was found to be significantly enhanced on co-culturing with the plant cells. The activity of phenylalanine ammonia lyase was observed to be related to the lignan accumulation indicating its role as the key enzyme of the phenylpropanoid pathway. The study resulted in lignan accumulation of 740 mg/L of the culture broth with a very high productivity of 52 mg/(L d). References Baldi, A., Jain, A., Gupta, N., Srivastava, A.K., Bisaria, V.S., 2008. Co-culture of arbuscular mycorrhiza-like fungi (Piriformospora indica and Sebacina vermifera) with plant cells of Linum album for enhanced production of podophyllotoxins: a first report. Biotechnol. Lett., PMID: 18427926. Farkya, S., Bisaria, V.S., Srivastava, A.K., 2004. Biotechnological aspects of the production of anti-cancer drug podophyllotoxin. Appl. Microbiol. Biotechnol. 65, 504–519. Varma, A., Sudha, S., Franken, P., 1999. Piriformospora indica—a cultivable plant growth promoting root endophyte with similarities to arbuscular mycorrhizal fungi. Appl. Environ. Microbiol. 65, 2741–2744.
doi:10.1016/j.jbiotec.2008.07.1804