Sample Literature Review On Carbazole

2.0 LITERATURE REVIEW

2.1 Heterocyclic compound

2.1.1 Carbazole

Carbazole is an aromatic heterocyclic organic compound. This compound has a tricyclic structure, comprising of two six membered benzene ring fused on either side of a five membered nitrogen-containing ring. The structure of compound is based on the indole structure in which a second benzene ring is fused onto the five-membered ring at the 2–3 position of indole (equivalent to the 4a–9a double bond in carbazole) (Nandy et al., 2014). Using conventional physico-chemical techniques is hard to remove this heterocyclic compound, is considered as the model compound in most of the denitrogenation studies and is produced during coal gasification (Liu et al., 2009). Several thousand tons

A number of carbazole degrading bacteria have been isolated and characterized including; Sphingomonas sp. GTIN11 by Kilbane et al. (2000); Pseudomonas sp. CA06 by Ouchiyama et al. (1993); Klebsiella sp. LSSE-H2 by Li et al. (2008) and Nocardioides aromaticivorans IC177 by Inoue et al. (2006). These finding show that carbazole degrading bacteria can be found in different genera (Farajzadeh & Karbalaei-Heidari, 2012). Interests in microbial degradation and transformation of carbazole have been growing for the past few years. Two bacterial strains were obtained that can degrade carbazole by a similar pathway which are Sphingomonas (Gai et al., 2007) and Pseudomonas (Li et al., 2006). The similar pathway which carbazole is firstly attacked at the angular position by dioxygenation, followed by of the dihydroxylated intermediate spontaneous conversion to 2-aminobiphenyl-2,3-diol. Then, the hydroxylated ring at the meta position attacked by an extradiol dioxygenase to give 2-hydroxy-6-(2-aminophenyl)-6-oxo- 2,4-hexadienoic acid. Anthranilic acid is produce resulting from hydrolysing of meta-cleavage, which is then totally mineralized (Gai et al., 2007; Wang et al.,

(1998) Gram staining is a technique of differentiating bacterial species into two large groups which are gram-positive and gram-negative. The name of this technique was comes from Hans Christian Gram that invented it. Gram staining differentiates bacteria by the chemical and physical properties of their cell walls by detecting peptidoglycan, which is present in a thick layer in gram-positive bacteria. The Gram stain is essential to the bacteria phenotypic characterization. The procedure of staining will distinguishes organisms of the domain bacteria according to structure of cell wall. A thick peptidoglycan layer and stain blue to purple indicate as the Gram-positive cells while a thin peptidoglycan layer and stain red to pink indicate as Gram-negative cells. In bacteriology, the most frequently used staining procedure is the Gram stain, is a complex and differential staining procedure. Organisms in the Domain Bacteria are differentiated according to cell wall composition over and done with a series of staining and decolorization steps. Cell walls of Gram-positive bacteria contain thick layers of peptidoglycan which 90% of cell wall and this stain are purple. Cell walls of Gram-negative bacteria have thin layers of peptidoglycan which 10% of wall, and high lipid content. These stain pink. Archeae or Eukaryotes phenotypic characterization not used staining procedure because both lack peptidoglycan. Applying a primary stain (crystal violet) to a