Impact assessment of azulene and chromium on growth and metabolites of wheat and chilli cultivars under biosurfactant augmentation

Dye azulene and heavy metal chromium are two different types of persistent toxic compounds present in textile effluent. These compounds contaminate the soil and harm plant productivity during unchecked disposal of textile effluent to the farm soil. Environmental and safety concerns associated with crops, soil, and human health encourage the exploration of biological tools to control the issue. We hereby propose the application of biosurfactant (lipopeptide) to reduce the toxic effects of azulene and chromium in plants. Results of the study indicated that the augmentation of biosurfactant with azulene and chromium promoted seed germination, plant biomass, specific leaf weight (SLW), chlorophyll content, protein content, soluble sugar and ascorbic acid concentration in cultivars of wheat and chilli. Decreasing the level of proline under biosurfactant augmentation further confirms the reduction of oxidative stress caused by azulene and chromium amendment. The results indicated that lipopeptide biosurfactant could be an effective biological tool to reduce the toxic effect of persistent substances in soil, thus maintaining soil health and sustainable agriculture.

Biodegradation of reactive textile dye Novacron Super Black G by free cells of newly isolated Alcaligenes faecalis AZ26 and Bacillus spp obtained from textile effluents

Bacteria were isolated from effluents of textile industries and screened by their capability to decolorize at least one of eight reactive dyes used in the textile industries. Three isolates having the capability to decolorize the highest number of dyes with more than 25% of decolorization were identified as Alcaligenes faecalis AZ26, Bacillus cereus AZ27 and Bacillus sp. AZ28 based on morphological, cultural, biochemical characteristics, and 16S rDNA sequence analysis. The decolorization capability of these three bacterial isolates was optimized under different physicochemical conditions by using Novacron Super Black G (NSB-G), one of the eight reactive dyes commonly used in textile industries. These bacterial isolates grew well in the presence of up to 500 mg L⁻¹ of NSB-G and showed decolorization of approximately 90% at 200 mg L⁻¹ of NSB-G after 96 h of cultivation at 37 °C and pH 8.0 under static condition. Decolorization of NSB-G by the bacterial isolates was investigated using UV-VIS spectrophotometry and Fourier Transform Infrared Spectroscopy (FTIR) analysis. The UV-visible absorbance spectra and the FTIR spectrum of the decolorized NSB-G significantly differed from those of the parent dye, indicating that the NSB-G was degraded by the bacterial isolates. High decolorization extent supports the notion that the bacterial isolates reported herein might have potential in the biological treatment of dyeing mill effluents.