Anjana Srivastava

Pesticides belonging to pyrethroid group are widely used in agricultural fields to check pest infestation in different crops for enhanced food production. In spite of beneficial effects, non-judicious use of pesticides imposes harmful effect on human health as their residues reach different food materials and ground water via leaching, percolation and bioaccumulation. Looking into the potential of microbial degradation of toxic compounds under natural environment, a cypermethrin-degrading Bacillus sp. was isolated from pesticide-contaminated soil of a rice field of Distt. Udham Singh Nagar, Uttarakhand, India. The bacteria degraded the compound up to 81.6 % within 15 days under standard growth conditions (temperature 32 °C pH 7 and shaking at 116 rpm) in minimal medium. Analysis of intermediate compounds of biodegraded cypermethrin revealed that the bacteria opted a new pathway for cypermethrin degradation. GC-MS analysis of biodegraded cypermethrin showed the presence of 4-propylbenzoate, 4-propylbenzaldehyde, phenol M-tert-butyl and 1-dodecanol, etc. which was not reported earlier in cypermethrin metabolism; hence a novel biodegradation pathway of cypermethrin with Bacillus sp. strain SG2 is proposed in this study.

This comprehensive review focuses on modified biochar and its applications as highly efficient adsorbent for the removal of contaminants from aqueous solutions. Biochar possesses favorable properties like numerous functional groups, large surface area, and charged surfaces, making it an appealing and environmentally friendly sorbent. However, designing biochar for precise pollutant removal necessitates evaluating variables like pyrolysis temperature, nature of biomass, biochar dosage, solution pH, composition, residence time, and physicochemical characteristics. Addressing these factors can amplify the adsorbent capacity of biochar. Various mechanisms, including pore filling, electron donor–acceptor (EDA) interactions, precipitation, electrostatic interactions, hydrophobic attractions, and ion exchange, contribute to pollutants’ adsorption. The current modification methods are often expensive and may lead to secondary pollution. Hence, the present review emphasizes methods of preparing environmentally friendly and financially affordable modified biochars for industrial and practical applications while minimizing adverse effects and maximizing positive outcomes for a sustainable future.

During bacterial growth an increased mRNA level is usually linked with higher rate of metabolism related to biodegradation of an unusual compound. In this study, quantitative gene expression data derived from mRNA level reveal the presence of pesticide degrading genes in 6 bacterial isolates showing biodegradation of cypermethrin (SG2, SG4), sulfosulfuron (SA2, Sulfo3), and fipronil (FA3, FA4). A correlation existed between the level of esterase coding mRNA and mineralization of cypermethrin in SG2 and SG4. Similarly the level of EST coding mRNA increased with biodegradation of fipronil and sulfosulfuron in FA3, FA4, SA2, and Sulfo3. Expression of est gene was observed in all the bacterial strains, but their level of expression was different. Bacterial strains SG4 and Sulfo3 showed higher level of est gene expression as compared to SG2, FA3, FA4, and SA2 and was in the range of approximately 30- to 60-fold, respectively, in comparison to control. Expression of genes for aldehyde dehydrogenase was observed in SG4 and Sulfo3. We report co expression of aldh (1000 bp) and est (∼550 bp) genes at the same time of pesticide induction/biodegradation.

The depletion of the world’s crude oil reserve, increasing crude oil prices, and issues related to conservation have brought about renewed interest in the use of bio-based materials. Emphasis on the development of renewable, biodegradable, and environmentally friendly lubricants has resulted in the widespread use of natural oils and fats. Vegetable oils are promising candidates as base fluid for eco-friendly lubricants because of their excellent lubricity, biodegradability, viscosity-temperature characteristics and low volatility. In view of agriculture based Indian economy, there is a great potential of producing vegetable oil based lubricants, which has ecological compatibility in addition to technical performance. However, suitability of the vegetable oils for a specific application either needs chemical modification or may be used as it is with additive blending route in order to get basestocks as per specifications for a particular end use application.   Key words: Biolubricants, vegetable oils, biodegradable, renewable.