Preface

The present book is a collection of 19 different articles from across the globe divided into four basic themes of Microbial Fertilizers, Microbial Metabolites, Microbes in Health and Microbial Fuels. The book with first chapter discusses removal of undesirable compounds from soil by a process called rhizoremediation. The use of plant-microbe interactions in the rhizosphere for bioremediation (rhizoremediation) of PAH in soil is described as an effective alternative to other remediation technologies. Sustainability of the ecosystem is the need of the hour which is pertinently covered in first sub-theme of this volume which focuses on plant-microbe-soil interactions comprising of three chapters based on microbial agents that can reduce the mammoth usage of synthetic fertilizers. The overuse of inorganic fertilizers has not only led to degradation of soil fertility, soil microflora and contamination of the ground water aquifers but also has reduced the produce quality due to accumulation of undesirable compounds in vegetables such as nitrates in spinach and lettuce. The use of bioinoculants is one of the effective tools for sustainable vegetable production which emphasizes prudent application and improving efficiency of applied inorganic fertilizers
by combining bioinoculant and organic farming practices. Bioinoculants including Phytohormone producing bacteria from plant and soils have the potentials as natural plant growth promoter in eco-friendly crop production as it also plays a role in promoting plant cell proliferation and elongation. Although not fully understood, metabolites do play an important role regulating traits involved in plant–microbe and microbes-microbes association. In addition to plants, some plant-associated microorganisms also produce IAA which might be used as a signaling molecule in microbial communication to induce the expression of genes involved in plant niche adaptation and colonization. Second sub theme of this collection of articles focuses on diverse types of microbial metabolites with chapters on biosurfactants, carotenoids, organic acids, antibiotics and biosensors, each of which is important and significant in its own way. It is well known that diverse groups of microbial surfactants have different natural roles which are specific to the physiology and ecology of the producing microorganisms. These roles confer them immense potential in various industrial sectors such as petroleum and petrochemicals, cosmetics, pharmaceuticals, mining and metallurgy, foods and beverages, agrochemicals, organic chemicals, and many others. They also have a potential candidature for use as antimicrobial agents, chemo-attractants, and stabilizing agents among others. Microbial antibiotics are one of the foremost metabolites sought after for their use as effective chemotherapeutic agents. The chapter discusses distribution and role of environmental Actinomycete species and goes on to discuss the antibacterial products already isolated which have been used commercially. They have evolved the capability of producing a variety of antibacterial substances, some 10,000 of which have already been discovered with at least 150 reaching pharmaceutical distribution. Next chapter on microbial carotenoids focuses on the major role they play in quenching singlet oxygen radicals and removing molecular oxygen from biological system without producing any oxidizing products. Scientific interest in dietary carotenoids has increased in recent years because of their beneficial effects on human health, such as lowering the risk of cancer and enhancement of immune system function, preventing the cell from damage which is described by their antioxidant potential. Last chapter in this theme discusses about Microbial sensors that can provide rapid measurement without labor-intensive and time-consuming sample preparation and apparently allow for a promising way to assess the biologically available water pollutants in the environment. The third sub theme of the book is enriched by discussion on microbes in health with four chapters, each explaining probiotics, direct fed microbials (DFMs), the role of microbes in production of vaccines, and survival mechanism of human pathogenic fungi. The chapter on Probiotics elucidates the role of microbiota in development of immune system and their influence on development of atopic conditions; and last but not least the importance of probiotics as a simple but powerful tool that may influence human health by modulating the microbiota. In the review on DFMs, dissemination and efficacy of Bacillus direct-fed microbial candidates in the gastrointestinal tract of broiler chickens and their effect on health and performance parameters in different poultry diets is discussed. Next on the coffee table is Vaccines, these have reduced the harmful impact of pathogenic microbes on human life. From the discovery of initial vaccines to modern vaccines, microbes have contributed significantly in their development and production as well. This chapter summarizes uses of microbes in the production of vaccines, including their use as source of antigens, in production of subunit vaccines, as source of adjuvant and their use as tools for genetic manipulations during vaccine production. The next chapter on the reader’s desk is about Long-chain polyunsaturated fatty acids (LC-PUFAs), such as the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) that provide significant health benefits. LC-PUFAs can be recovered from many marine organisms, transgenic plants, fungi and many microorganisms but the largest amount is currently extracted from fish. Heterotrophic microalgae are already being used commercially, in particular for DHA production as a food supplement. Last but not the least is the chapter on overview and an update on the survival mechanisms of human pathogenic fungi elucidated as the major pathogenic fungal species, Candida sp., Aspergillus sp. and Cryptococcus sp. Sustainability discussed in first sub theme has to be backed by processes which can reduce the environment pollution. This can be achieved by production of microbial fuels from incredible amounts of waste material lying unutilized, posing disposal problems and thus polluting our ecosystem. Biological fuels like biodiesel, bioethanol can be generated by efficient utilization of biotransforming ability of various microorganisms such as microalgae, cyanobacteria and yeasts covered in fourth sub theme of this volume with five engrossing chapters. This compendium presents applications of microbes encompassing diverse fields and serves as a reference book in its present capacity. The first book chapter in the fourth sub theme of the book discusses the current knowledge of different techniques for microalgal biofuel production, hydrogen production, biodiesel production via trans-esterification of the lipids and bioethanol via fermentation of sugar depending on the species as well as the bio-refinery approach. Another alternative substrate for biofuel production has been discussed in the form of whey during production of cheese. Due to the large volume of lactose generated during cheese processing, its transformation to bio-ethanol has been considered as environmental friendly whey valorization. Annual increase in global cheese-whey production can be utilized through microbial biotechnology in order to get newer biorefineries approach for successful production of green biofuels. Further, the book describes Bioethanol produced by bioconversion of cellulosic biomass increasingly used as a clean substitute of liquid fuel as it reduces environmental pollution and can also ease natural resource limitation. Hence the technology development for the production of ethanol has shifted towards the utilization of residual lignocellulosic material to lower the demand of oil import. Another chapter in this theme discusses the use of waste water for growth of microalgae. Integration of waste water treatment with microalgae performs nutrient incorporation to algal biomass, and waste water remediation as additional benefit. Thus the dual-process system provides the potential for energy and effective waste water treatment at lower costs compared to chemical treatment methods. This collection of articles can be useful for post graduate students, research students, lecturers, professors, and academicians related to Microbiology, Biotechnology, Biochemistry, Environmental Sciences, Fermentation Technology, Health Professionals, Agricultural Sciences, Applied Microbiologists and many more alike.

We would like to convey our sincere gratitude to all the subject experts and reviewers (Prof. Tofazzal Islam Islam, Prof. Mostafa El Sheekh, Prof. Piyush Pandey, Prof. Shadia M.Abdel-Aziz, and Dr. Ekta Khare) for their masterpiece erudite contributions. Funding received from UGC, New Delhi by Professor Neelam Garg for her research project at department of microbiology, Faculty of life Sciences, Kurukshetra University, kurukshetra, Haryana, India and Post Doctoral Fellowship to Dr. Abhinav Aeron from Chonbuk National University are is thankfully acknowledged. We extend our sincere appreciation to Donna Dennis, Carra Feagaiga, Stella Rosa and Gregoris Brito of Nova Science Publishers, USA for their valuable support to facilitate the completion of this book.