Bioremedial approach of Pseudomonas stutzeri SPM-1 for textile azo dye degradation.

The optimization of the bacterium Pseudomonas stutzeri SPM-1, obtained from textile wastewater dumping sites of Surat, Gujarat was studied for the degradation of the textile azo dye Procion Red-H3B. The strain showed significant activities of azoreductase (95%), laccase (76%) and NADH-DCIP reductase (88%) at 12, 10 and 8 h of growth, respectively, indicating the evidence for reductive cleavage of the dye. The optimization was carried on phenanthrene enrichment medium followed by exposing it to variable environmental factors and nutritional sources. The complete decolourization of dye (50 mg/L) happened within 20 h of incubation at pH 8 and temperature 32 ± 0.2 °C under microaerophilic condition. Decolourization was monitored with the shifting of absorbance peak in UV-Vis spectrophotometry and HPLC analysis. The changes in the functional groups were confirmed by the presence of new peaks in FT-IR data. GC-MS analysis helped in recognizing the degraded dye compounds thus elucidating the proposed pathway for Procion Red-H3B. The potential of bioremediation process was completed by phytotoxicity test using two plants Vigna radiata and Cicer arietinum. Our study concludes that the strain Pseudomonas stutzeri SPM-1, with its rapid decolourization efficiency holds noteworthy prospective in industrial application for textile wastewater treatment.

Microbial degradation of Procion Red by Pseudomonas stutzeri.

The bacterium Pseudomonas stutzeri SPM-1, obtained from textile wastewater dumping sites of Surat, Gujarat was studied for the degradation of the textile azo dye Procion Red-H3B. The optimization was carried on the phenanthrene enrichment medium followed by exposing it to variable environmental factors and nutritional sources. The complete decolorization of dye (50 mg/L) happened within 20 h of incubation at pH 8 and temperature 32 ± 0.2 °C under microaerophilic conditions. Decolourization was monitored with the shifting of absorbance peak in UV-Vis spectrophotometry and HPLC analysis. The physicochemical studies of effluent before and after the treatment revealed 85%, 90%, and 65% decline in BOD, COD, and TOC levels. The strain showed significant activities of azoreductase (95%), laccase (76%), and NADH-DCIP reductase (88%) at 12 h, 10 h, and 8 h of growth respectively indicating evidence for reductive cleavage of the dye. The changes in the functional groups were confirmed by the presence of new peaks in FT-IR data. GC-MS analysis helped in recognizing the degraded dye compounds thus elucidating the proposed pathway for degradation of Procion Red-H3B. The potential of the bioremediation process was concluded by a phytotoxicity test using two plants, Vigna radiata and Cicer arietinum. Our study demonstrates that the strain Pseudomonas stutzeri SPM-1 has rapid decolorization efficiency and holds a noteworthy perspective in industrial application for textile wastewater treatment.

Screening and identification of newly isolated Pseudomonas sp. for biodegrading the textile azo dye C.I. Procion Red H-3B.

AIM: To test the potential of a newly isolated strain of Pseudomonas sp., and its optimization for carrying out bioremediation of textile azo dye Procion Red H-3B. METHOD: The isolation of the bacterial strain was done from a textile waste dumping site, followed by screening techniques to study the decolourization of an azo dye. The isolated pure culture was selected by its ability to form clear zones. The biochemical tests gave partial confirmation of the isolates, and the phylogenic analysis made the complete confirmation by 16S rRNA sequencing. RESULT: The identified strain belongs to the genus Pseudomonas. The phylogenic analysis confirmed that the strain belongs to Pseudomonas stutzeri. The culture exhibited maximum decolourization at pH between 6 and 8, the optimum at pH 7·5 and 37°C temperature. A maximum of 96% discolouration was observed at 50 mg l-1 of initial dye concentration after 24 h of incubation period. At a dye concentration equally or greater than 600 mg l-1 , the colour removal was drastically decreased to 30%. The use of fructose at 1% (w/v) and peptone 0·5% (w/v) concentration for 24 h of incubation, as carbon and nitrogen source, showed luxuriant decolourization. The results showed that the Pseudomonas sp. holds immense potential in treating textile effluents containing the dye Procion red H-3B. CONCLUSION: Pseudomonas is a known organism in bioremediation of various textile dyes but not much has being reported about the role of P. stutzeri in the bioremediation of azo dyes. This study revealed the immense potential of this strain in degrading the azo dyes. SIGNIFICANCE AND IMPACT OF THE STUDY: The strain shows prospective for industrial application in the field of textile wastewater treatment. Bioremediation is comparatively cheaper and more effective treatment, thus holds promising future for a cleaner environment.

Circannual incidence of Giardia lamblia.

A circannual rhythm of Giardia lamblia positive stools was found by examination of records from three clinical laboratories in central Arkansas for the period 1980-1986. Cosinor analysis of monthly Giardia incidence based on stool specimen records from approximately 12,000 patients over the 7-year period revealed a circannual rhythm (P less than 0.001) on the basis of percent positive patients/month, with a computive acrophase occurring in late summer and minimum values in the winter. Patients involved in the study were primarily from the central Arkansas metropolitan areas, southern delta regions and northern mountainous regions of the state. Analysis of the data on the basis of total positive Giardia patients/month also revealed a circannual rhythm with the acrophase again occurring in late summer. The overall mean for percent positive stool specimens for the 7-year period was 5.3%, compared with the national average of 3.8% for G. lamblia positive stools. The data indicate that there may be a "Giardia season" in Arkansas since they could not be explained on the basis of day-care age distribution, or geographic origin. Awareness by epidemiologists, public health officials and other health care professionals of this circannual incidence of giardiasis is important for the prevention, diagnosis and treatment of this infectious disorder.