Environmental Sustainability

Urbanization and population expansion have increased the demand for scarce resources such as land, water, food, and energy. Furthermore, it has heightened environmental concerns, such as pollution and waste management. The difficulties above present significant challenges to the broader goal of attaining global sustainable development. As a result, there is considerable concern about sustainable waste recycling and management solutions. Among these efforts, expanding wastewater treatment facilities has emerged as a critical tool for environmental protection. As a result of the growth of wastewater treatment facilities, there has been a significant increase in sewage sludge (SS) production. Consequently, an urgent need exists to investigate alternative treatment and value-added methods for sewage sludge. This review looks at the current state of sewage applications for energy and resource recovery to foster sustainable development and industrial ecology through sewage sludge feedstocks. Furthermore, it aims to promote additional research into improving existing sewage sludge management systems, ensuring their cost-effectiveness, public acceptance, and environmental sustainability.

Halophilic archaea are multi-stress resistant organisms and their enzymes are of special interest as they are generally stable and functional under extreme conditions of temperature and low water activity. The search for novel extremozymes is an ongoing one because of their superior functionality in extreme conditions encountered in various industries. In this study, extremely halophilic archaea were isolated from two salterns (Marakkanam and Vedaranyam) in Tamil Nadu and from three salterns (Sinquetim, Siridao and Ribandar) in Goa, India. All isolates were Gram negative and their pigmentation ranged from light pink to bright orange. Characterization of the ten halophilic archaeal isolates was carried out by morphological, biochemical and molecular techniques. They spanned 6 different genera; Haloferax, Halorubrum, Halococcus, Haloarcula, Halogeometricum, and Haloterrigena. These extremely halophilic archaeal strains were screened for production of hydrolytic enzymes like amylase, esterase, lipase, protease, pectinase and cellulase. Amylase production by Halogeometricum sp. is being reported for the first time. All isolates showed at least one enzyme activity. Halococcus sp., Haloarcula sp., and Haloferax sp. were capable of producing three extracellular enzymes each. Cellulolytic activity was not observed in any of the isolates. Since these enzymes are inherently salt tolerant, they are very promising from the industrial point of view.

‘One health’ (OH) is a cross-sectoral approach that addresses human, plant, animal, and environmental health problems. The initiative stems from recognition of the convoluted linkages among global health risks and the need for coherent multipronged countermeasures. For agriculture, environmental degradation and biodiversity depletion wrought by heavy reliance on inorganic inputs to meet the needs of the ever-growing human population, are a matter of societal concern. Agroecological-based farming strategies have therefore aptly been promoted as an alternative. The push-pull technology (PPT), which was originally developed to combat stemborer pests and later the parasitic weed Striga is one such example. Undoubtedly, the PPT`s ability to maintain soil health and fertility, human and animal nutrition, and food safety together with crop protection against pests remains a progressive approach for buttressing food production among resource-constrained farmers in sub-Saharan Africa (SSA). In a bid to elevate its nutrition-sensitivity status, we recently intensified the cereal PPT by adding vegetables and legumes whilst simultaneously closing yield gaps through judicious usage of land, and environmental and crop protection based on farmer needs. Such context-based interventions, unlock new benefits for farmers and open new frontiers for research in pest and biodiversity management emanating from crop production infused with food safety and environmental stewardship. Whilst OH has largely received attention regarding animal health and zoonotics, we here opine how sustainably managed crop health, in the vegetable intensified PPT, contributes to the same outcomes through human and animal nutrition, food safety that bolsters developmental goals in gender equity and food security. We conclude that the cropping system can even contribute to fight against zoonotic diseases if companion plants that fend off diseases vectors are incorporated.

This study was aimed to evaluate inoculants of Azospirillum brasilense strain Ab-V5 supplemented with root exudates (collected from maize seedlings) for improving the inoculation response of maize, by stimulation of root colonization by the bacterium. Root exudates collected from seedlings of two commercial maize genotypes were evaluated, and their effects on seeds, seedling colonization and plant development under greenhouse conditions were addressed. Compared with seeds treated with water, seeds soaked with maize root exudate extract (MREE) increased mean bacterial count by three log-unity. Plantlets inoculated with MREE-supplemented inoculant suspensions showed 0.4 log-unity higher mean counts than those inoculated with non-supplemented bacterial suspension. The plant biomass for inoculants supplemented with MREE increased by 50% and the root area and number per plant increased by 19% when compared to non-supplemented bacterial suspensions. Photosynthetic physiological responses were also observed when the MREE inoculants were used, although these effects varied according to the plant genotype and MREE source. The results demonstrate that soluble compounds exuded by maize seedlings can increase the colonization of maize plants by A. brasilense Ab-V5 and suggest a strategy to improve the effectiveness of plant–PGPB associative systems by introducing chemoattractant molecules into inoculant formulations.

Thirteen accessions of Bacopa monnieri (L.) Wettst. were assessed for in vitro propagation, total bacosides, total phenol content and antioxidant potential. Nodal explants were cultured on Murashige and Skoog (MS) medium with 0.4 mg/L benzyl aminopurine (BA) to identify best accession based on growth parameters. The selected accession (IC 554588) was elicited with 1 mg/L of jasmonic acid, salicylic acid or malt extract to assess its efficacy in enhancing secondary metabolites production in in vitro cultures. Elicitor-treated plants showed increased production of bacosides (2.7–3.9 fold), total phenol content (5–18 fold) and higher antioxidant potential (7.9 fold) in 4 weeks. According to statistical analysis, antioxidant potential is highly correlated to total phenol as R-sq (adj) is 90.1%. Data was subjected to correlation, Principal Component Analysis (PCA) and cluster analysis to understand the relationship between different variables and identify major contributors of variability. Strong correlation between total bacoside, total phenol, and antioxidant activity indicate that elevated antioxidant potential was the result of overall increase in bacoside and phenol content, which can be enhanced by the application of elicitors. The study suggested that accessions IC 554588, IC 344312 and IC 554585 are elite and may be utilized for various pharmacopeias after further in vivo research and clinical trials.

Microbial communities from extreme environments, such as saline, arid, hot, cold, acidic, or alkaline are especially important because they have special genetic and physiological modifications to function properly under extreme environments. They possess extremozymes and other biomolecules that can be used in various industrial processes, e.g., pharmaceuticals, paper manufacturing, degradation of complex organic molecules, biofuel production and food industries. With the advent of new sequencing technologies and ‘omics’ approaches, such as metagenomics, metatranscriptomics and metaproteomics, new windows have been opened to study the microbial ecology and functional microbial communities from extreme environments. Recently, metaproteomic analysis has been extensively used to explore the functional microbial communities from various extreme environments around the globe. In this review, we have focused on the microbial diversity analysis, identification of novel proteins, and enzymes from extreme environments, through metaproteomic approaches.