Microbial decolouration of azo dyes: a review.

A series of short-term greenhouse experiments and laboratory incubations were conducted to evaluate the effect of macadamia (Macadamia integrifolia Maiden & Betche) nut shell (MNS) charcoal with varying volatile matter (VM) content on soil properties and plant growth in two tropical soils. Lettuce (Lactuca sativa L.) and corn (Zea mays L.) were planted in an Andisol amended with four rates of MNS charcoal (0, 5,10, and 20% w/w) containing relatively high VM content (225 g kg -1 ) with andwithout N fertilizer. Increasing rates ofcharcoalwithout N caused a significant decline in both lettuce and corn growth. Corn growth declined significantly with or without N at the two highest charcoal rates. In a third experiment, corn growth also declined significantly in an Ultisol amended with the MNS charcoal (5% w/w) with and without fertilizers. In a fourth experiment, charcoals with high VM (225 g kg -1 ) showed negative effects on plant growth while the low-VM (63.0 g kg -1 ) charcoal supplemented with fertilizer showed a significant positive effect on corn growth. Results from the 2-wk incubation experiments showed that high-VM charcoal caused a significant decline in soil NH 4 + -N and a significant increase in soil respiration compared with the soil amended with low-VM charcoal and the soil alone. We propose that phenolic compounds and other products in the high-VM charcoal stimulated microbial growth and immobilization of plant-available N. Our results demonstrate that VM content appears to be an important property of charcoal that has short-term effects on soil N transformations and plant growth. Longer incubation experiments and field trials are needed to further elucidate the role of charcoal VM content on soil processes and plant growth.

Charcoal Volatile Matter Content Influences Plant Growth and Soil Nitrogen Transformations

Kinetics, isotherms and thermodynamic modeling of liquid phase adsorption of Rhodamine B dye onto Raphia hookerie fruit epicarp

Biological valorization of low molecular weight lignin

Fungal decolouration and degradation of azo dyes: A review

Phenol and its derivatives are one of the largest groups of environmental pollutants due to their presence in many industrial effluents and broad application as antibacterial and antifungal agents. A number of microbial species possess enzyme systems that are applicable for the decomposition of various aliphatic and aromatic toxic compounds. Intensive efforts to screen species with high-degradation activity are needed to study their capabilities of degrading phenol and phenolic derivatives. Mostofthecurrentresearchhasbeendirectedattheisolationandstudyofmicrobial species of potential ecological significance. In this review, some of the best achievementsindegradingphenoliccompoundsbybacteriaandyeastsarepresented,which draws attention to the high efficiency of strains of Pseudomonas, Candida tropicalis, Trichosporon cutaneum, etc. The unique ability of fungi to maintain their degradation potential under conditions unfavorable for other microorganisms is outstanding. Mathematical models of the microbial biodegradation dynamics of single and mixed aromatic compounds, which direct to the benefit of the processes studied in optimization of modern environmental biotechnology are also presented.

Microbial degradation of phenol and phenolic derivatives

http://www.dzumenvis.nic.in/Biodegradation/pdf/Biodegradation%20of%20high%20amounts%20of%20phenol.pdf

Biodegradation of high amounts of phenol, catechol, 2,4-dichlorophenol and 2,6-dimethoxyphenol by Aspergillus awamori cells

The plasmid gene cat-86 specifies chloramphenicol-inducible chloramphenicol acetyltransferase in Bacillus subtilis. Induction by the antibiotic is primarily due to activation of the translation of cat-86-encoded mRNA. It has been suggested that the inducer stalls ribosomes at a discrete location in the leader region of cat-86 mRNA, which causes the destabilization of a downstream RNA secondary structure that normally sequesters the cat-86 ribosome binding site. It is the destabilization of this RNA secondary structure that permits translation of the cat-86 coding sequence. In the present report, we show that ribosomes that were stalled in the cat-86 leader by starvation of host cells for the amino acid specified by leader codon 6 induced gene expression to a level above that detected when cells were starved for the amino acids specified by leader codons 7 and 8. Starvation for amino acids specified by leader codons 3, 4, or 5 failed to activate cat-86 expression. These results indicate that the stalled ribosome that is most active in cat-86 induction has its aminoacyl site occupied by leader codon 6. To determine if chloramphenicol also stalled ribosomes in the cat-86 regulatory leader such that the aminoacyl site was occupied by codon 6, we separately changed leader codons 3, 4, 5, and 6 to the translation termination (ochre) codon TAA. Each of the mutated genes was tested for its ability to be induced by chloramphenicol. The results show that replacement of leader codons 3, 4, or 5 by the ochre codon blocked induction, whereas replacement of leader codon 6 by the ochre codon permitted induction. Collectively, these observations lead to the conclusion that cat-86 induction requires ribosome stalling in leader mRNA, and they identify leader codon 6 as the codon most likely to be occupied by the aminoacyl site of a stalled ribosome that is active in the induction.

Chloramphenicol induction of cat-86 requires ribosome stalling at a specific site in the leader.

Biodegradation of toxic organic components from industrial phenol production waste waters by free and immobilized Trichosporon cutaneum R57

The industry is a major source of pollution for water ecosystems. Industrial production of textile, cellulose and various chemicals is connected with synthetic dyes usage. The discharged effluents could have a hazardous influence on the environment. The biological treatment for synthetic dyes removal is a very perspective, environmentally protective and low cost approach for solution of such problems. One of the often used and very important in dyeing of cellulosic fabrics and textile industry dyes is the anthraquinone-base chlorotriazine dye, known as Reactive Blue 4. Decolorization of Reactive Blue 4 by Trametes versicolor strain 1 was investigated. The experiments were carried out with different concentrations of dye (50mg/l and 125mg/l) and glucose (1, 2 and 3%) in a medium. The enzyme activity of laccase (EC 1.10.3.2) was measured during the process of decolorization. It was shown that there was a direct correlation between the observed enzyme activity and the investigated process effectiveness. It was established that the best conditions for laccase production and decolorization of 125mg/l Reactive Blue 4 dye are in a medium containing 3% glucose. In these conditions 90% Reactive Blue 4 was decolorized for 384 hours.

/pdf/decolorization-of-synthetic-dye-reactive-blue-4-by-mycelial-4wvba1rulz.pdf

Zlatka Alexieva

Papers

Microbial degradation of phenol and phenolic derivatives

Biodegradation of high amounts of phenol, catechol, 2,4-dichlorophenol and 2,6-dimethoxyphenol by Aspergillus awamori cells

Chloramphenicol induction of cat-86 requires ribosome stalling at a specific site in the leader.

Biodegradation of toxic organic components from industrial phenol production waste waters by free and immobilized Trichosporon cutaneum R57

Decolorization of synthetic dye reactive blue 4 by mycelial culture of white-rot fungi trametes versicolor 1