eChapters

The study of soil microorganisms involves various complicacies when compared with those of plants or animals aboveground. The complicated heterogeneous environment existing in soil and the varied growth behaviour of microbial populations in soil have necessitated the development of special techniques to study the microbes and their metabolic diversity, individually and holistically without disturbing their natural habitat. With the gradual improvement in microscopy since its discovery in 1667 and also with the greater understanding of the nature of soil microbes and their properties in relation to total ecosystem function, the concept of studying microbes in isolation has enormously changed. Microscopes have helped in magnifying these, otherwise invisible, minute creatures within the limits of naked eyes.

SINGLE CELL PROTEIN (SCP) AND PROTEIN DEFICIENCY

Protein is an essential component of diet. The greatest single problem in the world today is global food protein shortage. Having adequate quantity of food is only one side of the picture, but the most important aspect is the supply of balanced and nutritious food. All efforts are being made to increase the food production through modern methods of farming. But very little attention is being paid towards protein requirements and production. Approximately half of world population suffers from the protein deficiency disease called ‘Kwashiorkor’ and children with poor protein are victims of this disease.

Usually, cereals have low protein values while protein rich pulses are not available in desired quantities due to poor yields and high costs. The good quality protein available in fish, meat, poultry, and eggs is not available due to poor economic condition as well as varied dietary habits. With the current system of production, agriculture cannot be relied upon to feed an ever increasing world population. Hence there is an urgent need to find other protein sources. The best potential is seen in microbial protein or single cell protein (SCP), a new source of protein independent of agriculture.

DEFINITION: The dried cells of microorganisms such as bacteria, fungi, yeasts, algae that are grown in large scale culture systems as proteins for human or animal consumption are collectively known as "single cell proteins".

2.1 Introduction 
The world is encountering a severe power and environmental crisis. Adopting sustainable progress is the best means to protect our environment and maximise the use of available resources. The urgent issues, encompassing diverse types of pollution and carbon emissions, highlight the necessity to shift towards renewable energy sources. This shift is essential for diminishing our dependence on fossil fuels, addressing the on-going challenges regarding climate change, and confronting the exhaustion of current energy reserves. Furthermore, mitigating water pollution is an essential component of ensuring ecological sustainability [1,2]. Water supplies are rapidly being contaminated due to diverse contaminants including heavy metals, and harmful chemicals. While industrialization is critical for societal growth, it is critical to recognise the negative environmental consequences caused by numerous processes that emit hazardous substances. Improper disposal of untreated wastewater can negatively impact ecology and biodiversity [3]. As a result, it is critical to use environmentally friendly and sustainable treatment methods that adhere to green development principles. This will bolster industrialization efforts while upholding water pollution safeguards for recovery and reuse. Given the prevailing energy crisis, traditional wastewater treatment facilities have become financially unsustainable due to their high energy consumption. Traditional wastewater treatment is both costly and demands substantial energy resources. Furthermore, these approaches fall short of efficiently eradicating recalcitrant organic waste, heavy metals, and other persistent contaminants. Moreover, many of these treatment processes require regeneration. Microbial fuel cell (MFC) technology has emerged as an ecofriendly treatment option capable of effectively eliminating stubborn organic pollutants and heavy metals over the long term. Microbial fuel cells are chosen over other current treatment methods because to their reduced energy needs and lower chemical usage [4,5]. In addition to lowering energy usage, MFCs possess the ability to produce ample bioenergy, which can help alleviate the energy shortage. This provides a cleaner alternative for generating renewable energy in favour of sustainable development and environmental protection as depicted in Figure 2.1.

Introduction

Hippocrate, an ancient physician, a great thinker and also often referred as father of medicine, for the first time conceive the idea nearly 2,500 years ago that a disease is caused due to natural factors such as environmental factors, diet, and living habits. He advocated the secret of healthy living in healthy food in his famous quote “Let food be thy medicine and medicine be thy food”. But unfortunately, this wisdom about food has faded with the time and we became dependent on synthetic medicines and drugs for even life style disorders. In the last century, research advancement in the field of food science and nutrition established food not only as a source of nutrition but also a source of active food components that aid specific functions and rejuvenated the Hippocrates concept. According to the Department of Health and Human Services, USA, daily diet of a person, plays a crucial role in 5 of 10 diseases which are the leading causes of death, such as diabetes (noninsulin dependent or type 2), stroke, coronary heart disease (CHD), specific type of cancer, and atherosclerosis. In the mid-1980s, term “functional food” was introduce in Japan and defined as food that contain active components either from plant or animal origin and provide physiological benefits in addition to the basic nutritional needs.

Genetics is the study of what genes are, how they carry information, how their information is expressed, and how they are replicated and passed to subsequent generations or other organisms.

DNA in cells exists as a double-stranded helix; the two strands are held together by hydrogen bonds between specific nitrogenous base pairs: A-T and C-G.

A gene is a segment of DNA, a sequence of nucleotides, that code for a functional product, usually a protein.

When a gene is expressed, DNA is transcribed to produce RNA; mRNA is then translated into proteins. This is also referred as Central Dogma of Life. The DNA in a cell is replicated before the cell divides, so each daughter cell receives the same genetic information.

The term growth for bacteria and other microorganism usually refers to changes in the total population rather than an increase in size or mass of an individual organism. As the mechanism of conservation and dissipation of heat generated during metabolism lacks in bacteria, the enzyme system in bacteria gets directly influenced by temperature. The purpose of studying the bacterial growth curve is a) to become familiar with the population growth dynamics of bacterial culture and b) to plot a growth curve and determine the generation time of bacterial culture.

A number of methods are now available for measuring bacterial growth. Some important ones are

1)By colony counting or cell counting

2)By weighing the cells

3)By cell activity (turbidity method)

Abstract

Discovery of the agricultural utility of microbes during the later part of the eighteenth century, led to the formulation and utilization of superior microbial strains as biofertilizers, for a wide variety of crops and growing conditions across the world. Though microbial inoculants have been in usage for almost two centuries, they are yet to capture the collective imagination of farmers across the globe, which is essential to meet the larger objective of reducing chemical input usage in cropping systems. One probable reason for this is the existence of large growing tracts that are subject to various abiotic stresses of atmospheric and edaphic origin, which limit the proliferation and efficiency of the microbial strains that are commonly used in inoculant production.  This is obvious, since unlike chemical fertilizers, microbial cells being living systems need to grow and thrive in the introduced eco-systems in order to achieve the desired effects of inoculation. But unfortunately microbial inoculant technology has largely adopted the one size-fit all mindset, which had led to failures of microbial inoculants especially in abiotically stressed growing environments. In such a scenario it would be wise to adopt a location or region specific approach for the selection of superior and locally adapted microbial strains for inoculant production.

Introduction

The increasing concern about the long-term productivity of agro ecosystems has emphasized the need to develop a management strategy that maintains and protects the soil resources. This is directly related to the maintenance of the level of soil organic matter and nitrogen status, which are the critical components of soil productivity. These parameters can change over time due to crop management practices such as cultivation, crop rotation, residue management or fertilization which, in turn, can influence the long-term sustainability of ecosystem. Application of chemical fertilizer is one of the most expensive inputs in agriculture. About 65% of the applied nitrogenous fertilizer is lost from the plant–soil system through gaseous emissions, runoff, erosion and leaching which causes greenhouse effects and nitrate pollution of surface and ground water (Rejesus and Hornbaker 1999). Similarly, P applied in soil is rapidly fixed and results in low P availability for plant production. In this context, the deployment of microbial biofertilizers promise increasing soil nutrient availability in integrated nutrient management system.

The increase in population and global industrialization has led to environmental pollution, which is a significant threat to the health of the ecological system. Different measures are recommended to remediate polluted areas effectively. The applications of nanotechnology in medicine, cosmetics, sports, textiles, and pharmaceuticals have increased over the years. Another approach to remediate the adverse effects of pollutants on the environment is by utilizing nanotechnology for contaminant remediation. Biogenic nanoparticles are tiny particles produced by biological entities such as fungi, bacteria, yeast, and algae. These biogenic nanoparticles are efficient in removing pollutants like heavy metals, pharmaceutical waste, dyes, and hydrocarbon waste. 

1.    Introduction    174
2.    The Thermodynamic and Mechanistic basis of Cellular Metabolism    174

    2.1.      Adenosine triphosphate, 175
    2.2.    Coenzyme A, 176
    2.3.    Modes of ATP synthesis, 177

3.      Components of Electron Transport Chain    181

    3.1.    Electron carriers in ETC, 182
    3.2.    Complex I - NADH dehydrogenase (NADH coenzyme Q reductase), 185
    3.3.    Complex II - Succinate - coenzyme Q reductase, 187
    3.4.    Complex III - Coenzyme Q - cytochrome c reductase, 187
    3.5.    Complex IV - Cytochrome c oxidase, 188
    3.6.    ATP synthese, 188

The essential nutrients and their function in microbial cells

1. INTRODUCTION

Flavour is a distinctive property of a substance affecting the gustatory sense. It may be defined as “The sum of those characteristics of any material taken in the mouth, perceived principally by the senses of taste and smell, and interpreted by the brain.” Flavour perception is a complex process which requires the particles to be mixed with saliva and salivary enzymes to promote the release of flavour. Flavour molecules are very diverse in nature. More than 5000 compounds in food have been identified as flavour components which can be detected at very low concentration and are thus, used in products at very low levels. Hexenols and hexenals, characteristic of green taste of fresh fruits and vegetables, can be perceived at a concentration of about 1 part per million (ppm). Naturally occuring flavour compounds are present at a very low concentration ranging from parts per trillions (ppt) to parts per millions (ppm) level. Majority of these compounds are volatile, with boiling points in the range of 20-300 °C. Most of these compounds are lipophilic and possess a great diversity of chemical group and structure with molecular weight ranging between 50-250 g/mol.

Flavour and fragrance compounds are a part of expanding industry with an estimated cost of nearly $27 billion. These comprise of diverse molecules with unique structures and functional groups that contribute to varied aroma and flavour, ranging from floral to fruity notes. The processing operations modify the equilibrium between the different components in raw food that might weaken the original flavour, which require subsequent supplementation. These flavour supplements can be natural or chemically synthesized. Of all the available flavour compounds, around 80% are produced by chemical synthesis whose use is limited due to formation of racemic mixtures and lack of substrate specificity. The growing awareness of consumers towards chemicals supplemented to food has led to the development of the flavouring compounds of biological origin referred to as natural flavours or bioflavours. The first major source of flavour compounds was primarily from plants. Identification of microbes producing vital food flavourants paved the way for alternative low cost, efficient and flexible method for the commercial production of flavour compounds.

Abstract
 
Opencast mining destroys the original land ecosystem and microbial community due to mining and stockpiling of mine rejects on adjoining land, which is a matter of great environmental concern. Mining creates formation of wastelands, formation of gullies, ravines, overburdens, reduced water infiltration and increased runoff. Reclamation of mined out areas is often difficult due to its chemical, physical and biological traits. Absence of topsoil is the most common feature of the mine spoils dumps. Arbuscular mycorrhizal fungi (AMF), the synonym of VAM fungi, are important microbes of soil that form symbiotic association with most of the terrestrial plants on the earth. Observations led to use of legume microsymbionts as biological substitutes for fertilizers. AMF diversity increases with species diversity of plants as the potential number of association increases. Dominant arbuscular mycorrhizal fungi can prevent the invasion of non-mycorrhizal plants on land where they have established symbiosis and promote their mycorrhizal host.

Introduction

Bacteria are very minute and colourless in their natural environment and are difficult to be seen under compound microscope. To view their exact morphology, various kinds of stains are used. Stains are of three main types.

Acidic stains: These are those stains in which charge on dye ion is negative. e.g. India Ink, Eosin etc.

Basic stains: These are those stains in which charge on dye ion is positive. e.g. Methylene blue, Crystal violet etc,

Neutral stains: These are the salts of dye acid in dye base. e.g. Eosinate of Methylene blue.

Abstract

Anaerobic sulfur compound reduction processes make use of sulfur, thiosulfate, trithionate, tetrathionate, and sulfite during the reduction process. Complete reduction of these sulfur compounds leads to production of H₂S. Isolation of sulfur compound reducers requires a suitable electron donor and one of the sulfur compound as a sole electron acceptor during the reduction process carried out in anaerobic conditions. Anaerobic sulfur, thiosulfate and tetrathionate reductases identified to date are molybdopterin binding oxidoreductases that extract out electron during the reduction process. The electron transport chain during the reduction process involves cytochromes and menaquinones. Dissimilatory sulfite reductases include conventional siroheme dissimilatory sulfite reductase and the nonconventional sulfite reductases including ASR sulfite reductase, F₄₂₀ dependent sulfite reductase and the MccA sulfite reductase. Anaerobic sulfur compound reduction process are almost ubiquitous in nature and are important part of the biogeochemical cycle. They occurs in aquatic systems, are found in extreme environments such as hydrothermal vents, acid mine drainage sites and are also found in important human and animal pathogens.

Abstract

Microbiological synthesis of nanoparticles has emerged as rapidly developing research area in nanotechnology across the globe with various biological entities being employed in production of nanoparticles constantly forming an impute alternative for conventional methods. Simple prokaryotes to complex eukaryotic organisms including higher plants are used for the fabrication of nanoparticles. In the present article, the synthesis of important plant nutrients like Mg, Zn, Ag, Au, Ti, P and Fe nanoparticles from different fungal species, their characterization and application potential of nanonutrients in agriculture is elaborately discussed.

Introduction

A toxin (Greek: ôïîéêüí, toxikon, lit. (poison) for use on arrows) is a poisonous substance produced by living cells or organisms that is active at very low concentrations. Toxins can be small molecules, peptides, or proteins and are capable of causing disease on contact or absorption with body tissues by interacting with biological macromolecules such as enzymes or cellular receptors. Toxins vary greatly in their severity, ranging from usually minor and acute (as in a bee sting) to almost immediately deadly (as in botulinum toxin)