Chryseobacterium indologenes and Enterococcus faecalis were isolated from activated sludge of textile wastewater treatment plant. These bacteria had the ability to decolorize several azo-dyes. Degradation of azo dyes was initiated by decolorization (reduction of azo bond) which occurred in anaerobic condition. In this study, we focussed on biodegradation of Orange II by pure culture of C. indologenes ID6016 and E. faecalis ID6017, and to determine the metabolite products of Orange II degradation. The degradation of Orange II by both bacteria was carried out in batch experiments using liquid medium containing 80 mg/l Orange II, under sequential static agitated incubation. During the bacterial growth under static incubation (6 h), 66.1 mg/l Orange II were decolorized by 35.54 mg/l biomass of E. faecalis ID6017, but no decolorization found with C. indologenes ID6016. Based on HPLC results, the decolorized Orange II products were identified as sulfanilic acid and amino-naphthol. These metabolites were probably used or degraded by C. indologenes ID6016 under agitated incubation.

A B S T R A C TFungi can survive in various environments with different media including wood. Lignin in timber is hard to be degraded and hydrolyzed efficiently because of its polymer form, composite and complex structure. Ligninolytic fungi produce an extracellular enzyme to withstand with toxic or mutagenic chemicals exposure and known to degrade different types of pollutant compounds. Lignin decomposers were also known to play a significant role in the pulping process of paper mills, used in waste treatment such as textile and hydrocarbon wastes. This study was conducted to obtain fungal isolates that have delignification capability and to compare the ability of fungal isolates in degrading lignin. Isolates were from rotten wood and soil using selective lignin medium with tannic acid as sole C source. This study characterized the isolates by their morphology and identified them using Morphology and Taxonomy of Fungi book by Bessey (1950). The ligninolytic capability comparison was conducted by measuring the transparent zone formed on selective lignin media. This research found 14 isolates of fungi and all of them had the ligninolytic capability. Aspergillus niger isolate has the highest ligninolytic capability by producing 6.45 cm clear zone diameter on the 7th day of incubation. Aureobasidium sp. has the smallest clear zone diameter of 1.9 cm within the same period.

The objectives of this study were to investigate: (1) the capacity of Enterococcus faecalis on the decolorization of the azo dyes Acid Red 27 and Reactive Red 2; and (2) the growth characteristics of E. faecalis on those dyes. E. faecalis was able to decolorize Acid Red 27 and Reactive Red 2 effectively. High decolorization efficiency (95-100%) was achieved within 3 h of incubation for Acid Red 27, and 12 h for Reactive Red 2, at room temperature, neutral pH, static and non-aerated condition. Growth characteristics of E. faecalis on azo dyes, which were indicated by cell growth rate, biomass production, and growth yield, was worse than the control. E. faecalis grew better on Acid Red 27 rather than Reactive Red 2.

Phosphorus is the most important key element in the nutrition of plants. Although P is abundant in soils, it is a major limiting factor for plant growth as it is in an unavailable form for roots uptake. Phosphate solubilizing bacteria (PSB) has ability to convert insoluble form of P to an available form. This study was aimed at screening and characterizing phosphate-solubilizing bacteria from manure and different rhizosphere and to ascertain a potential benefit to use mixed cultures to improve P solubilization. A total of 12 PSB colonies were isolated on Pikovskaya’s agar medium containing tricalcium phosphate. Out of 12 bacterial isolates, 2 isolates showed high phosphate solubilization index (2.17 and 1.83, respectively) were selected for further study. Based on the 16S rRNA gene sequence analysis, PSB3 was closely related to Burkholderia contaminans (99%), and  PSB11 was closely related to Acinetobacter baumannii (99%). The mean P dissolved in liquid cultures of PSB3 and PSB11 in a 14-day incubation were 96.7 and 39.3 mg l-1, respectively. Mixed inoculation of B. contaminans PSB3 and A. baumannii PSB11 could not increase the solubilization activity significantly, suggesting there is antagonistic behavior of one isolate towards another. As the interaction of these two isolates may be antagonistic, co-inoculation of these bacteria for P solubilization is not recommended. However, further study is needed to confirm these results.

Polyamide 4, which is composed of repeating unit of γ-aminobutyric acid (GABA), is a biobased and biodegradable polymer since it can be synthesized from renewable material instead of fossil-based material. GABA is produced by decarboxylation of glutamate (Glu) using glutamate decarboxylase (GAD: EC 4.1.1.15), which is produced by some microorganisms. In this study, enzymatic conversion of GABA from glutamate by Lactococcus lactis and Escherichia coli cell and chemical polymerization of GABA to polyamide 4 were revealed. The results show that GAD activity of E. coli was higher than that of L. lactis. The treatment of E. coli cell by heating and sonication increased the GAD activity and conversion rate of glutamate to GABA was up to 70.5%. The optimum temperature for this conversion is 37ºC. On the other hand, chemical synthesis of polyamide 4 was catalyzed by heating GABA at 215ºC for 2 minutes.