In this study, biological degradation of 2,4,6-trinitrotoluene (TNT) which is very highly toxic environmentally and an explosive in nitroaromatic character was researched in minimal medium by Bacillus cereus isolated from North Atlantic Treaty Organization (NATO) TNT-contaminated soils. In contrast to most previous studies, the capability of this bacteria to transform in liquid medium containing TNT was investigated. During degradation, treatment of TNT was followed by high-performance liquid chromatography (HPLC) and achievement of degradation was calculated as percentage. At an initial concentration of 50 and 75 mg L(-1), TNT was degraded respectively 68 % and 77 % in 96 h. It transformed into 2,4-dinitrotoluene and 4-aminodinitrotoluene derivates, which could be detected as intermediate metabolites by using thin-layer chromatography and gas chromatography-mass spectrometry analyses. Release of nitrite and nitrate ions were searched by spectrophotometric analyses. Depending upon Meisenheimer complex, while nitrite production was observed, nitrate was detected in none of the cultures. Results of our study propose which environmental pollutant can be removed by using microorganisms that are indigenous to the contaminated site.

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Degradation of 2,4,6-trinitrotoluene (TNT), a nitroaromatic explosive found in the soil and ground water, was investigated using Pseudomonas aeruginosa in in vitro experiments . Biodegradable abilitiy of this bacteria was performed with 50 and 75 mg L −1 TNT concentrations in a defined liquid medium for 96 h time period. Treatment of TNT in supernatant samples taken at 0, 6, 12, 24, 48, 72 and 96 h from agitated vessels was followed by reverse-phase high-performance liquid chromatography (HPLC). In cultures supplemented with 50 and 75 mgL −1 TNT, after 96 h of incubation 46% and 59% reduction were detected respectively. Two metabolites as degradation intermediates with nitrite release into the medium, 2,4-dinitrotoluene (2,4-DNT) and 4-aminodinitrotoluene (4-ADNT), were elucidated by thin layer chromatography (TLC) and gas chromatography-mass spectrometry (GC-MS). These findings clearly indicate that Pseudomonas aeruginosa can be used in bioremediation of TNT contaminated sites.

Yenilebilir filmlerin sağlık açısından güvenilir olması, basit teknoloji gerektirmesi, üretim maliyetlerinin düşük olması ve çevreyi kirletici etkilerinin olmaması en önemli avantajlarıdır. Gıdanın raf ömrünü uzatan ve paketleme materyalinin ekonomik verimliliğini artıran yenilebilir filmler için kullanılan en yeni materyallerden biri kitosandır. Kitosan, yengeç, karides, istakoz gibi eklembacaklıların kabuklarında, bazı bakteri ve mantarların hücre duvarlarında bulunan ve doğada selülozdan sonra en yaygın olarak bulunan bir polimer olan kitinin deasetilasyonu sonucu elde edilmektedir. Kitosan hemostatik, bakteriyostatik, fungistatik, spermisidal, antikanserojen, antikolesteremik, antiasid, antiülser, yara ve kemik iyileşmesini hızlandırıcı, immün sistem stimülan gibi önemli biyoaktif özelliklere sahiptir. Bu özelliklerinin yanı sıra film oluşturabilme ve bariyer özellikleri kitosanı antimikrobiyal özellikte yenilebilir film ve kaplamalar için ideal bir materyal haline getirmektedir. Özellikle sebze ve meyvelerin kalitelerinin korunması ve depolama sürelerinin artırılmasında kitosanın kullanım potansiyeli ortaya konulmuştur. Gıdaların kitosan film ile kaplanması ambalaj içindeki kısmi oksijen basıncını azaltmakta, gıda ile çevresi arasındaki nem transferi ile sıcaklığı kontrol altında tutmakta; su kaybını azaltmakta, meyvelerde enzimatik kahverengileşmeyi geciktirmekte ve solunumu kontrol etmektedir. Bunlara ilave olarak doğal aromanın arttırılması, tekstürün ayarlanması, emülsifiye edici etkinin artırılması, rengin stabilizasyonu ve deasidifikasyon gibi konularda da kitosandan yararlanılmaktadır. Requirement simple technology, low production costs, lack of polluting effects and reliability in terms of health of it is the most important advantages of edible films. Chitosan that extend the shelf life of food and increase the economic efficiency of packaging materials is one of the new materials used for edible films. Chitosan was obtained by deacetylation of chitin which is the most commonly occurred polymer after cellulose in nature, in shells of arthropods such as crab, shrimp, lobster and in cell walls of some bacteria and fungi. Chitosan has the important bioactive properties such as hemostatic, bacteriostatic, fungistatic, spermicidal, anticarcinogenic, anticholesteremic, antacids, antiulcer, wound and bone healing accelerator and stimulating the immune system. As well as these features, the film forming and barrier properties of its, chitosan is made the ideal material for edible films and coatings in antimicrobial characters. Especially, in the protection of qualities and the improving storage times of fruits and vegetables, have been revealed the potential use of chitosan. The coating food with chitosan films reduces the oxygen partial pressure in the package, maintains temperature with moisture transfer between food and its environment, declines dehydration, delays enzymatic browning in fruits and controls respiration. In addition to, chitosan are also used on issues such as the increasing the natural f...

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