Spentwash is one of the most complex and cumbersome wastewater with very high BOD, COD and other organic and inorganic toxic constituents. It is dark brown colored and diffi cult to treat by normal biological process such as activated sludge or anaerobic lagooning. The color is due to the presence of melanoidins, caramels and other polymers. These compounds have anti oxidant properties which render them toxic to microorganisms. Spentwash disposal into the environment is hazardous and has a considerable pollution potential. It affects the aesthetic merit. Its decolorization by physical or chemical methods have been investigated and were found unsuitable. In the recent past, increasing attention has been directed towards utilizing microbial activity for decolorization of spentwash. This review reveals various groups of microorganisms which have potential in spentwash decolorization. The role of enzymes in decolorization and the microbial degradation of individual compounds imparting color to spentwash are also discussed.

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Abstract:The effect of three different extraction methods, namely supercritical CO 2 , soxhlet and solvent methods on the yield, efficiency, physico-chemical properties, nutritional, anti-nutritional composition, antimicrobial and antioxidant activities of moringa (Moringa oleifera Lam.) seed kernel oil was investigated in this study. Oil extraction for SC-CO 2 were 37.76 g/100g and 98.43%, observed to be higher than those of soxhlet extraction (29.12 g/100g and 76.29%), and significantly lower than solvent extraction (22.12 g/100g and 57.99%). The physico-chemical composition of the oils showed considerable variation among the extraction methods. The SC-CO 2 extracted oil was found to be of superior quality, showing negligible thermal degradation and exhibited significantly (p<0.01) higher nutritional and antioxidant activity and lower anti-nutritional composition than the soxhlet and solvent extracted oils. Oils produced by SC-CO 2 and soxhlet extraction methods had antimicrobial activities higher than solvent extracted oil. SC-CO 2 extracted oil was found to have maximum number of bioactive compounds (14 compounds) followed by solvent (8 compounds) and soxhlet (4 compounds) extracted oil. The results of the study demonstrated that SC-CO 2 would be a promising process for the extraction of moringa seed kernel oil of premium quality.

In this study, a total of 50 halophilic bacterial isolates were screened for 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity, of these six with the highest ACC deaminase activity were selected for an increase in chickpea yield under salinity. The ACC deaminase activity among the isolates was ranged between 0.12 and 3.56 mM α-KB mg−1 min−1. These six isolates and one reference strain from the Agricultural College, Raichur, were used in the microcosm experiment during the rabi season of 2018. After 60 days of sowing, decreased rhizosphere pH and electrical conductivity (EC) from 8.4 to 7.6 and 4.3 to 3.4 dS m−1, respectively, were reported in chickpea. Among the treatments, Bacillus safensis (B. safensis)-inoculated plants showed a higher number of flowers (71 flowers/plant), pods (49.3 pods/plant), branches (33.3 branches/plant), and enhanced fresh weight (17.2 g/plant) and dry weight (8.1 g/plant). They were corroborated by improved nitrogen and phosphorus absorption of 71.5 and 43.5%, respectively, in B. safensis-treated plants. Based on the microcosm experimental findings, three cultures improving biometric and yield attributes were chosen for the field investigation. The field study was carried out at the Agricultural Research Station, Ganagavathi, during Kharif 2019. The chickpea plants treated with the consortium [B. safensis, Pseudomonas stutzeri, and Staphylococcus xylosus] increased the superoxide dismutase and catalase activity of plants by 258 and 196%, respectively. In addition, an increase in ascorbate peroxidase activity (0.41 μmol of ascorbate oxidized s−1 g−1 fresh weight) in the leaves and proline content was also recorded. The consortium (B. safensis, P. stutzeri, and S. xylosus) significantly increased nutrient uptake (N and P), the number of flowers, number of pods, and yield by 63.26, 39.03, 110, 59.96, and 17.56%, respectively, in chickpeas. Finally, inoculation with a mixture of three isolates is an effective method for increasing chickpea production under osmotic stress.

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