Biodegradation Of Naphthalene And Biosynthesis Of Indigo By Naphthalene-Degrading Bacteria

The biodegradation of naphthalene can eliminate naphthalene in environment to decrease pollution. In addition, as catalyst, enzyme or cells in biodegradation process which may involve in biotransformation of naphthalene, have important significance to social development and green chemical industry. Naphthalene is the most familiar polycyclic aromatic hydrocarbon and exists in all of the waters in the world. Due to the potential toxicity, and the higher and higher concentration in environment, naphthalene has evoked abroad attention in the world range. Indigo is a traditional pigment extensively used in the printing and dyeing, pharmaceutical and food industry. Aniline is a latent carcinogenic substance which is vastly used in the reaction of chemosynthesis of indigo. Biosynthesis of indigo has signality in reduce operating costs and decrease energy consumption and enhance the manufacture security and environment security.Naphthalene-degradaing bacteria Hydrogenophaga Pallcronii LHJ38 can grow on naphthalene as sole energy and carbon source. The growth and naphthalene degradation curve of the strain were determined in biphase and monophase system respectively. The growth and naphthalene degradation activity of cells from oil phase and aqueous phase were compared carefully. It is higher more than 4 fold, the maximum biomass of 4.248g/l. was achieved after 72h incubation under the optimum conditions of 3mL paraffin oil and 0.2g naphthalene in 100mL mineral salt medium (MSM), than the MSM monophase system. In the biphasc system, the naphthalene degradation capacity of Hydrogenophaga Palleronii LHJ38 was higher more than 2 times than that in the monophase system. The naphthalene (2g/l.) can be degraded completely in 132h by adding 10mL·cell suspension (0.2mg dry weight cell/mL). The naphthalene degradation rate of cells from oil phase was 2.7 fold as fast as that of cells from aqueous phase.The biosynthesis of indigo by naphthalene-degradaing bacteria Hydrogenophaga Palleronii LHJ38 from indole in mineral medium and on solid agar medium has been studied. Indigo formation capacity by Hydrogenophaga Palleronii LHJ38 cell growing in mineral salts medium in the presence of salicylate greatly increased. Contrarily. indigo formation capacity by Hydrogenophaga Palleronii LHJ38 cell growing in LB medium in the presence of salicylate decreased by 2 fold. The optimum pH ranges for biosnythesis of indigo formation by Hydrogenophaga Palleronii LHJ38 growing in LB medium at pH 8.95 increased 2 fold compared with that at pH 6.95.