Durgesh Kumar Jaiswal

Potassium as an Important Plant Nutrient in Sustainable Agriculture: A State of the Art

The current scenario of potassium (K) depletion in soil is slowly increasing due to K fixation or the unavailable form of K in soil. Presently, farmers are faced with a problem of higher price of K fertilizer or other fertilizers in market so farmers are unable to fulfill the demand of potassium in soil for plant growth. Potassium deficiency affects the nutritional quality, mechanical stability, and also pathogen resistance of crops. Therefore, that times needs to fallow the sustainable technology for sustainable agricultural production through use of microbial consortia of potassium-solubilizing microbes or biofertilizer/PGPR under organic farming system. The potassium-solubilizing microorganism is one of the best sustainable technologies, which solubilizes the fixed form of K available for plant uptake. Thus, the bio-formula of the potassium-solubilizing microorganism as biofertilizer offers environmentally sustainable approach and also fulfills the requirement of potassium for crop production.

Book Review: Advances in Biodegradation and Bioremediation of Industrial Waste.

This book covers broader aspect of bioremediation and biodegradation of environmental pollutants. The pollution due to industrialization is a global challenge for the sustainable development of human beings. Environmental pollutants may be organic or inorganic, like heavy metals, pesticides, toxic chemical fertilizers, polyaromatic hydrocarbons, polychlorinated biphenyls, detergents, antibiotics, lubricants, nanoparticles, paints, and disinfectants and many of them may cause various diseases in human beings and animals. After the green revolution, the indiscriminate use of chemical fertilizers and pesticides for enhancing agricultural productivity has destroyed the soil fertility and health as well as microbial flora and fauna. The industrial waste and sewage contain hazardous organic and inorganic chemicals comprising heavy metals, salts and extreme pH. Long term cumulative effects of heavy metals in the environment are detrimental to human health. The degradation and bioremediation of industrial wastes are a challenging task because there is no reliable technology till date which is sustainable in terms of complete removal of these pollutants. Ultimately, diverse groups of microorganism that are already present in the nature may provide solution for the degradation and bioremediation of toxic industrial wastes. Microorganisms are being used for the bioremediation and transformation of pollutants from long times (Okpokwasili, 2007). Bioremediation involves the application of microbes to detoxify and degrade environmental pollutants. Microbes have various mechanisms for removing heavy metals from contaminated environments, such as adsorption to cell surfaces, complexation of exopolysaccharides, intracellular accumulation, biosynthesis of metallothionins and other proteins that trap metals and transform them to volatile compounds (Sharma et al., 2013). Recently, research is being focused in the development of genetically modified microbes or consortia for the detoxification of environmental pollutants. The book consists of 14 chapters covering the available advanced knowledge in biodegradation and bioremediation of various environmental pollutants, which are a real challenge to environmental researchers in the current scenario. The 1st, 12th, and 14th chapters highlight recent advances in phytoremediation and the role of the bacterial ecology of the rhizosphere of wetland plants for bioremediation of complex industrial wastewater. Some plant species have the inherent capacity to uptake and accumulate the heavy metals whereas other species help in biodegradation and biotransformation of toxic pollutants to nontoxic form of pollutants for environmental management. The phytoremediation of heavy metals is broadly discussed in terms of plant mechanisms for removing theses pollutants from soils and wastewaters. The 2nd, 3rd, 7th, and 10th chapters highlight the microbial degradation and bioremediation of heavy metals, aromatic compounds, hexachlorocyclohexane (HCH) pesticides and textile dyes from industrial waste and other environmental contaminants. This book has explored the latest information related to research and development of bioremediation of various xenobiotics compounds. The 5th chapter highlights the significance and role of biosurfactants and bioemulsifiers for bioremediation and biodegradation of various pollutants discharged from industrial waste, showing to be a sustainable biotechnological tool for minimizing the toxicity of industrial waste. The 6th, 8th, 11th, and 13th chapters specially discuss the aerobic and anaerobic biodegradation of lignocellulosic, agriculture and lipid wastes. The application of potential microbial enzymatic processes for bioremediation and biodegradation of environmental pollutants is discussed in the 4th chapter. This chapter addresses laccases and their significance in the bioremediation of industrial effluents. Laccase enzyme is a type of multicopper blue oxidase which oxidize a broad range of organic substrates such as phenols, polyphenols, anilines, and even certain inorganic compounds. It is extensively disseminated in higher plants, fungi, insects, and bacteria. The 9th chapter covers few laboratory scale bioremediation experiment on petroleum hydrocarbons of contaminated wastewater of refinery plants. In general, the process of phytoremediation and microbial biodegradation is a comparatively cheaper and relevant approach on a large scale than physical and chemical remediation. The editor tried to make a holistic approach to all bioremediation and biodegradation techniques applicable for minimization of environmental pollution (soil, oily sludge, and groundwater) caused by petroleum hydrocarbons, solvents, pesticides, and other chemicals. However, management of some of the pollutants generated by tanneries, distilleries, and paper and pulp industries are a challenging task mainly due to the lack of appropriate acquaintance regarding the persistent organic pollutants discharged from these industries and the process of their detoxification. Similarly, the safe dumping and biodegradation of hospital waste is also an authentic challenge worldwide for human and animal health. In last, this book compiles and updates the recent literature related to microbial degradation and phytoremediation of industrial, agricultural waste and their biochemical and molecular processes for reducing the environmental pollution. In addition, the book also provides current available tools, techniques and literatures regarding bioremediation and biodegradation of industrial waste. It also describes the significance of various bioreactors for the treatment of complex industrial waste and provides specific chapters on bioreactors and membrane process integrated with microbial degradation processes. Thus, this book is useful to the environmental engineering students for designing sustainable technology for biodegradation and bioremediation of industrial wastes. All chapters give information regarding role of microbes and plants, and their consortium for the degradation of recalcitrant chemicals. It also covers the advances in basic knowledge as well recent technologies in environmental biotechnology. Hence, this book will be highly beneficial for a broad range of readers, including students, researchers, scientists, teachers, and consulting professionals in industrial biotechnology, environmental microbiology, biochemistry, molecular biology, life sciences and agricultural sciences.

Microbe Induced Degradation of Pesticides in Agricultural Soils

The extensive use of pesticides has played hazard with living beings and the environment and also these chemicals persist and leach in environment for a long time because of more water solubility, tendency to adsorb to the soil (soil adsorption) and more half-life that is tendency to persistence in the environment. The indigenous microbial strains are more effective pesticide degrading microbes because they are survived and grow very well in particular soil environment than exo-genic microbes which brought from other agro-climatic region. In this chapter, we have attempted to discuss the recent challenge of pesticide problem in soil environment and their degradation by the use of effective indigenous pesticides degrading microorganism. Therefore, the use of pesticide degrading microbial consortia is an eco-friendly technology for sustainable agriculture production.

The Significance of Plant-Associated Microbial Rhizosphere for the Degradation of Xenobiotic Compounds

Currently, remediation of xenobiotic compounds (heavy metals and hydrocarbons, pesticides, persistent organic pollutants (POPs) in the soil and water has become a major problem. Xenobiotic compounds in the soil exert alternations in the functionality of ecologically and agronomically important soil microflora. These chemicals get accumulated in lipid tissues of higher organisms and cause many problems to the human health (like immunosuppression, hormone disruption, reproductive abnormalities and cancer). Remediation of xenobiotic pollutants by the conventional approaches based on physicochemical methods is economically and technically challenging. But bioremediation techniques based on plant roots and their associated microbes are the most promising, efficient, cost-effective and sustainable technology. A variety of chemicals like organic acids, amino acids and phenolic compounds are secreted by such plants as root exudates. These compounds play a significant role in the interaction between plant root and microbes and also are helpful to stimulate the survival rate and the efficiency of microbes against xenobiotic pollutants. In this chapter, we describe how plant root-associated microbes help in the remediation of xenobiotic compounds and the impact of xenobiotic compounds on microbial community as well as their application feasibility on the basis of these attributes.

Characterization and Screening of Thermophilic Bacillus Strains for Developing Plant Growth Promoting Consortium From Hot Spring of Leh and Ladakh Region of India

In the present investigation, the main aim is to identify and characterize the potential drought tolerant plant growth promoting consortium for agricultural productivity. Three bacterial isolates were isolated from hot spring of Chumathang area of Leh district. Bacillus species (BHUJP-H1, BHUJP-H2, and BHUJP-H3) were done some biochemical tests including catalase, cellulase, amylase, indole-3-acetic acid, phosphate solubilisation, production of ammonia, siderophore, and hydrogen cyanide. Molecular characterization of isolates was done by 16S rDNA sequencing, e.g., Bacillus subtilis BHUJP-H1 (KU312403), Bacillus sp. BHUJP-H2 (KU312404) and B. licheniformis BHUJP-H3 (KU312405). The genetic diversity of the isolates was assessed by seven inter simple sequence repeat, all primer shows high polymorphism. The highest polymorphism efficiency and polymorphism information content showed by UBC-809 and UBC-836 which were 100% and 0.44 respectively, the lowest is by UBC-807 75% and 0.28 respectively. On an average 90.69% polymorphism efficiency and 0.40 polymorphism information contents obtained by used markers. The highest, 11.08 and the lowest, 4.50 effective multiplex ratios obtained for primer UBC-823 and UBC-807, on an average 7.99 effective multiplex ratio obtained. The highest, 4.89 and the lowest, 1.25 marker indexes obtained by UBC-836 and UBC-807 respectively and on an average 3.24 obtained. The UPGMA cluster analysis divided a population into two clusters I and II, in which BHUJP-H1 and BHUJP-H2 grouped under same while BHUJP-H3 grouped under another cluster. The treatment combination of Bacillus subtilis BHUJP-H1, B. subtilis BHUJP-H1+ B. licheniformis BHUJP-H3 and B. subtilis BHUJP-H1+ Bacillus sp. BHUJP-H2+ B. licheniformis BHUJP-H3 were recorded better combination for enhancing plant growth attributes of Vigna radiata as compared to control and others. The plant growth promoting consortium, e.g., Bacillus subtilis BHUJP-H1, Bacillus subtilis BHUJP-H1+ B. licheniformis BHUJP-H3 and B. subtilis BHUJP-H1+ Bacillus sp. BHUJP-H2+ B. licheniformis BHUJP-H3 can be further used as effective microbial inoculant for enhancing the production of mungbean in field conditions. Bacillus sp. BHUJP-H1 and Bacillus sp. BHUJP-H2 may use as drought tolerant plant growth promoting consortium for enhancing the sustainable agricultural productivity.

Consequence of phosphate solubilising microbes in sustainable agriculture as efficient microbial consortium: A review

Phosphorus is an essential nutrient for plant growth and yield. Currently, phosphorus fixation in soil is a major problem throughout the world as available phosphorus in soil is highly reactive with cationic elements to form complex compounds. Rock phosphate is one of the cheapest fertiliser and most abundant; however, its direct application in soils is not much effective for the availability of phosphorus to plant growth due to its low reactivity. Further, phosphorus is present as a fixed or complex form in soils, which is unavailable for plants. Phosphate solubilising microbes (PSMs) have potential to solubilise the complex form of phosphate in the available form of phosphorus to plants. PSMs have different mechanisms for solubilisation of phosphate by producing various acids and enzymes. Other mechanisms of phosphate solubilisation and mineralisation follow chelation and immobilised cell technology. All such phosphate solubilisation mechanisms by PSMs have been discussed in this article. The current need to develop genetically modified PSM as efficient PSMs strains for sustainable agricultural production is also discussed in the present review. The PSMs is known as effective biofertiliser for enhancing the plant growth, yield and nutrient content in crops as well as improve the soil fertility under sustainable agriculture. The main aim of this review was to elaborate the phosphate solubilising activities and their consequences for sustainable agriculture.