Over the past few decades, the rapid development of agriculture and industries has resulted in contamination of the environment by diverse pollutants, including heavy metals, polychlorinated biphenyls, plastics, and various agrochemicals. Their presence in the environment is of great concern due to their toxicity and non-biodegradable nature. Their interaction with each other and coexistence in the environment greatly influence and threaten the ecological environment and human health. Furthermore, the presence of these pollutants affects the soil quality and fertility. Physicochemical techniques are used to remediate such environments, but they are less effective and demand high costs of operation. Bioremediation is an efficient, widespread, cost-effective, and eco-friendly cleanup tool. The use of microorganisms has received significant attention as an efficient biotechnological strategy to decontaminate the environment. Bioremediation through microorganisms appears to be an economically viable and efficient approach because it poses the lowest risk to the environment. This technique utilizes the metabolic potential of microorganisms to clean up contaminated environments. Many microbial genera have been known to be involved in bioremediation, including Alcaligenes, Arthrobacter, Aspergillus, Bacillus, Burkholderia, Mucor, Penicillium, Pseudomonas, Stenotrophomonas, Talaromyces, and Trichoderma. Archaea, including Natrialba and Haloferax, from extreme environments have also been reported as potent bioresources for biological remediation. Thus, utilizing microbes for managing environmental pollution is promising technology, and, in fact, the microbes provide a useful podium that can be used for an enhanced bioremediation model of diverse environmental pollutants.

Beneficial microbiomes for bioremediation of diverse contaminated environments for environmental sustainability: present status and future challenges

Soil, the skin of the Earth is one of the fundamental natural resource and important component that contributes to the ecosystem. Soil performs a wide range of ecosystem services like food production, climate and water regulation, provision of energy and inhabiting various life forms. This fundamental natural resource of ecosystem is a home of diverse ranges of microbes (beneficial and pathogenic) known as soil microbiome, which are grouped into three domains i.e. archaea, bacteria, eukarya (fungi, algae and nematodes) of life. Diversity of soil microbiome varies with environment and their existence. They exist in bulk soil as well as root influenced soil. Soil microbes also show their existence in the different extreme environments. The microbial genera such as Achromobacter, Arthrobacter, Azospirillum, Azotobacter, Bacillus, Burkholderia, Exiguobacterium, Flavobacterium, Herbaspirillum, Methylobacterium, Paenibacillus, Pseudomonas, Rhizobium, Serratia and Staphylococcus have been reported as predominant in all the different conditions of soil. All the different groups of microbes present in the soil naturally plays a several significant roles like nutrients cycling, recycling of ground water, maintenance of soil fertility, decomposition of organic matter and formation of fossil fuels. As their role in environment these microbes may have several applications and can be used as in agriculture as plant protector and plant growth enhancer. Soil microbes can also be used in the environment for pollutants remediation and decomposition purposes. Present review deals with the biodiversity of beneficial soil microbiomes and their potential biotechnological contribution for nutrient cycling, plant growth improvement and nutrient uptake.

Biodiversity, and biotechnological contribution of beneficial soil microbiomes for nutrient cycling, plant growth improvement and nutrient uptake

Although the development and progression in agriculture have increased crop production, in return, it has resulted in various health problems. International Labour Organization has considered the agricultural sector as one of the most hazardous to health worldwide. Many hazardous toxic non-biodegradable chemical compounds like, persistent organic pollutants, xenoestrogens are persisting in the agricultural environment, and have entered the food chain as well as started accumulating in agriculture workers. Farmers are highly exposed to biological, chemical and environmental hazards but can sustain their life by taking home remedies as well as breathing fresh air released by plants, but the risk associated with chemicals, heat, musculoskeletal injuries, noise, poisonous insects, reptiles, grain bins and silos still prevail. We need to take utmost care of the agriculture sector people and educate them with new concepts of farming and simultaneously understand the experiences gained by them. We need to increase the level of health education, safety literacy and subsequently improve the farmers’ quality of life for improved living standards. This book chapter provides an overview of the health hazards associated with modern agricultural practices and suitable alternatives to cope up with them.

https://link.springer.com/content/pdf/10.1007%2F978-981-15-6949-4_16.pdf

Potential Strategies for Control of Agricultural Occupational Health Hazards

The beneficial associations of plants and microbes exemplify a complex and multi-organ system composed of participatory organisms and the environmental forces acting on them. Current knowledge of plant-microbe symbiosis involves a series of associations with varying degrees of intimacy and mutual dependence. Generally, rhizosphere microbes can help the plant by maintaining nutrient recycling, hormones production, preventing microbial infections and improving tolerance towards potentially hazardous compounds. Symbiotic relationships are known to be extremely beneficial for the enhancement of overall plant growth, especially in those soils that are deprived of certain minerals like P or N. However, in case of well-fertilized arable soils, symbiotic microbial growth is found to reduce significantly due to the improved bioavailability of nutrients in the soil. In addition to the vast benefits of symbiotic microbial growth in the rhizosphere, it also offers an overall increase in crop productivity, therefore making it an essential area of research.

Plant–Microbe Association for Mutual Benefits for Plant Growth and Soil Health

A systematic review on the implementation of advanced and evolutionary biotechnological tools for efficient bioremediation of organophosphorus pesticides.

Microbes can be incorporated into a particular area where it can interact with selected pollutants and convert them into nontoxic or relatively less toxic compounds by excellent colonization in plant roots, thereby helping in the degradation of pollutants. This process is called ‘rhizoremediation’ which serves to emphasize the role of rhizosphere having competent microbes. These days majority of the process involving the degradation of environmental pollutants occurs through rhizospheric microbes. Root exudates can be taken as the best food source that is available in the soil for these microbes. The plants’ uptake of heavy metals from soils in high concentrations negatively influences the interaction of microbes with plants, its growth and consequently the crop’s production and yield. Heavy metals behave as genotoxic substances, and they disintegrate different cell organelles, rupture the cell membranes and disturb the physiological process like carbohydrate metabolism, protein synthesis and respiration photosynthesis. Some of the species of the pseudomonad family are root colonizer, having high efficiency for remediating pollutants via phytoremediators. In the previous two decades, various research articles on rhizodegradation of different toxicants utilizing diverse plants or potentially microbial inoculants have been documented.

Rhizoremediation: A Unique Plant Microbiome Association of Biodegradation

Microorganisms like bacteria, yeast, or fungi have the capabilities to degrade or transform hazardous chemicals like benzene, toluene, polychlorinated biphenyls (PCB), dioxins, etc. into nontoxic or less toxic substances, known as microbial bioremediation. It has been used for treating contaminated water and soil. It involves the promotion of growth of specific microflora which is local to that contaminated sites. Various approaches can be used for promoting the growth of microflora like incorporation of nutrients and addition of electron acceptors molecules or controlling temperature and moisture. Contaminants play the role of nutrients for microorganisms in bioremediation. Generally it involves biodegradation and biotransformation which convert the hazardous substances to non-hazardous or less-hazardous form with the production of carbon dioxide or methane, water, and biomass. Microorganisms which are considered for bioremediation are Actinobacteria, Alcaligenes, Flavobacterium, Mycobacterium, Mycococcus, Nitrosomonas, Penicillium, Phanerochaete, Pseudomonas, Serratio, Trametes, and Xanthobacter. Many petroleum hydrocarbons like benzene, toluene, and O-xylene (BTX) have been biodegraded by Pseudomonas putida MHF7109. Pseudomonas nitroreducens PS-2 has been found useful for bioremediation of pesticide chlorpyrifos. Cow dung microflora has been found for bioremediation for benzene. Treatment technologies are being used; still organic pollutants are existing in the soil and water beyond their normal limit; hence bioremediation along with recombinant DNA technology can be a significant tool to remove toxic substances.

Significance and Approaches of Microbial Bioremediation in Sustainable Development

The Bryophyllum pinnatum refers to the family Crassulaceae. The glycoprotein from the 0.9% of normal saline extracts of Bryophyllum pinnatum leaves was refined by dialysis with 50% of ammonium sulfate. Protein concentration was invented by Lowry’s method. The dialyzed sample allowed for SDS-PAGE to determine the molecular weight (Mr ). The antioxidant activity of crude lectin extract has been assessed by the DPPH (1, 1-Diphenyl-2-picrylhydrazyl) and ABTS methods. The present study aims to verify the antioxidant activity of lectins detached from the leaves of Bryophyllum pinnatum.

/pdf/antioxidant-activity-of-lectin-isolated-from-leaves-of-99l99b1djq.pdf

Sruchi Devi

Papers

Rhizoremediation: A Unique Plant Microbiome Association of Biodegradation

Significance and Approaches of Microbial Bioremediation in Sustainable Development

Antioxidant activity of lectin isolated from leaves of bryophyllum pinnatum