No abstract

The tremendous increase in human population and industrialization has exacerbated the existing problem of water pollution to a great extent. The textile industry is the major cause of this problem due to its significant use of organic synthetic dyes as coloring materials during the dyeing process. The presence of color in wastewater is a major environmental concern, as these dyes are resistant to degradation by physio-chemical treatments. Bioremediation is an attractive method that can completely degrade these dyes while also being cost-effective. This comprehensive review aims to provide a brief insight into bioremediation based on some of the latest emerging wastewater treatment technologies for the removal of synthetic dyes. Starting with the importance of decolorization of synthetic dyes and their environmental impacts, different physio-chemical treatment technologies are analyzed with a special emphasis on their limitations. The bioremediation of textile wastewater with detailed biodegradation mechanisms using different bacterial species (bacteria, fungal, algae, enzyme, and mixed culture) under aerobic and anaerobic conditions is thoroughly discussed. In this article, the major factors affecting the implementation of biological treatment are explained. In addition, the latest emerging treatment technologies, such as nano-bio materials, genetic engineering, phytoremediation, electro-bioremediation (microbial electrochemistry technology, MET), and integrated/hybrid technologies (such as biological processes with physio-chemical processes, electro-coagulation, adsorption, ultra-filtration, membrane, and advanced oxidation) are critically reviewed; their challenges and the future perspectives in textile wastewater treatment are also highlighted.

No abstract

Antimicrobial activity of the acetone, methanol and ethanol extracts of some common lichen species such as Usnea longissima Ach., Everniastrum cirrhatum (Fr.) Hale, Peltigera polydactylon (Neck.) Hoffm. and Sulcaria sulcata (Lév.) Bystr. ex Brodo & D. Hawksw., were screened in vitro against six clinically important pathogenic bacteria, Staphylococcus aureus, Streptococcus faecalis, Bacillus cereus, Pseudomonas aeruginosa, Salmonella typhimurium and Escherichia coli by Kirby-Bauer technique of disc diffusion method. Minimum inhibitory concentration was taken out by Broth micro dilution method according to the NCCLS guidelines. Acetone, methanol and ethanol extracts of the investigated lichens showed relatively strong antimicrobial activity against all the gram positive bacteria and two gram negative bacteria. It was found that the inhibition zone of tested bacteria against lichen extracts varied between 7.6 -30.7 mm diameters. The lowest MIC value was observed to be as low as 6.25 µg/ml against B. cereus of U. longissima. Generally the lichen extracts tested demonstrated antimicrobial effect which suggests a possibility of their use in treatment of various diseases caused by these and similar microorganisms.Key words -Kirby-Bauer method -Lichenized fungi -MIC -pathogenic bacteria. IntroductionLichens are composite organisms consisting of symbiotic association of a fungus (the mycobiont) with a photosynthetic partner (the photobiont or phycobiont), usually either a green alga or cyanobacterium. Lichens are unique in nature and physiology because they look and behave quite differently from their component organisms. Lichens produce a wide range of organic compounds that can be grouped as primary metabolites and secondary metabolites (Elix 1996). Primary metabolites such as proteins, lipids, carbohydrates, and some other organic compounds are produced by both the partners and are needed for the lichen's metabolism and structure. Secondary metabolites are produced by the fungus alone and secreted onto the surface of lichen's hyphae either in amorphous forms or as crystals. The secondary metabolites include aliphatic,

No abstract