The application of microbial strains as axenic cultures has frequently been employed in a diverse range of sectors. In the natural environment, microbes exist as multispecies and perform better than monocultures. Cell signaling and communication pathways play a key role in engineering microbial consortia, because in a consortium, the microorganisms communicate via diffusible signal molecules. Mixed microbial cultures have gained little attention due to the lack of proper knowledge about their interactions with each other. Some ideas have been proposed to deal with and study various microbes when they live together as a community, for biotechnological application purposes. In natural environments, microbes can possess unique metabolic features. Therefore, microbial consortia divide the metabolic burden among strains in the group and robustly perform pesticide degradation. Synthetic microbial consortia can perform the desired functions at naturally contaminated sites. Therefore, in this article, special attention is paid to the microbial consortia and their function in the natural environment. This review comprehensively discusses the recent applications of microbial consortia in pesticide degradation and environmental bioremediation. Moreover, the future directions of synthetic consortia have been explored. The review also explores the future perspectives and new platforms for these approaches, besides highlighting the practical understanding of the scientific information behind consortia.

With the increasing resistance exhibited by undesirable bacteria to traditional antibiotics, the need to discover alternative (or, at least, supplementary) treatments to combat chemically resistant bacteria is becoming urgent. Quorum sensing (QS) refers to a novel bacterial communication system for monitoring cell density and regulation of a network of gene expression that is mediated by a group of signaling molecules called autoinducers (AIs). QS-regulated multicellular behaviors include biofilm formation, horizontal gene transfer, and antibiotic synthesis, which are demonstrating increasing pathogenicity to plants and aquacultural animals as well as contamination of wastewater treatment devices. To inhibit QS-regulated microbial behaviors, the strategy of quorum quenching (QQ) has been developed. Different quorum quenchers interfere with QS through different mechanisms, such as competitively inhibiting AI perception (e.g., by QS inhibitors) and AI degradation (e.g., by QQ enzymes). In this review, we first introduce different signaling molecules, including diffusible signal factor (DSF) and acyl homoserine lactones (AHLs) for Gram-negative bacteria, AIPs for Gram-positive bacteria, and AI-2 for interspecies communication, thus demonstrating the mode of action of the QS system. We next exemplify the QQ mechanisms of various quorum quenchers, such as chemical QS inhibitors, and the physical/enzymatic degradation of QS signals. We devote special attention to AHL-degrading enzymes, which are categorized in detail according to their diverse catalytic mechanisms and enzymatic properties. In the final part, the applications and advantages of quorum quenchers (especially QQ enzymes and bacteria) are summarized in the context of agricultural/aquacultural pathogen biocontrol, membrane bioreactors for wastewater treatment, and the attenuation of human pathogenic bacteria. Taken together, we present the state-of-the-art in research considering QS and QQ, providing theoretical evidence and support for wider application of this promising environmentally friendly biocontrol strategy.

Zinc is one of the micronutrients, required by all types of crops. About 10–100ppm of zinc is present in soil which is generally immobile. The cow dung sustains all life and being practice since aeons. Exploitation of cow dung bacteria can mobilize nutrients besides contributing in sustainable agriculture. Therefore, to examine mobilization of Zn, cow dung is used as a source of bacteria. The objectives of the present study were to isolate an array of bacteria from cow dung and to characterize them for their Zn (ZnO and ZnCO₃) mobilization ability in addition to establish the optimum conditions for dissolution of zinc. A total of seventy bacterial isolates have been screened for Zn mobilization. Out of which most potent (CDK15 and CDK25) were selected to study the effect of various parameters viz. pH, temperature and concentration of Zn. These parameters were assessed qualitatively in diverse growth medium and quantitatively using Atomic absorption spectroscopy. Optimum pH and temperature for mobilization was recorded at pH 5 (ZnO) and 37 °C (ZnCO₃) by CDK25, whereas, optimum zinc concentration for mobilization was recorded at 0.05% (ZnO) by CDK15. Maximum amount of Zn solubilized was recorded by CDK25 in ZnO (20ppm). Considering the abilities of most potent bacterial isolates with reference to P-mobilization and growth promoting traits, pot culture assay of C. annuum L. was carried out. The findings of which conclude that, bacterium CDK25 (Bacillus megaterium) could be exploited for factors viz. nutrient management of Zn, growth promoting agent, and Zn augmentation in soil.