22.Microbial Biotechnology: fundamentals of applied microbiology

Microbes (or microorganisms) are organisms that are too small to be seen by the unaided eye. They include bacteria, fungi, protozoa, microalgae, and viruses.

Microbes live in familiar settings such as soil, water, food, and animal intestines, as well as in more extreme settings such as rocks, glaciers, hot springs, and deep-sea vents. The wide variety of microbial habitats reflects an enormous diversity of biochemical and metabolic traits that have arisen by genetic variation and natural selection in microbial populations.

Historically, humans have exploited some of this microbial diversity in the production of fermented foods such as bread, yogurt, and cheese. Some soil microbes release nitrogen that plants need for growth and emit gases that maintain the critical composition of the Earth's atmosphere.

Other microbes challenge the food supply by causing yield-reducing diseases in food-producing plants and animals. In our bodies, different microbes help to digest food, ward off invasive organisms, and engage in skirmishes and pitched battles with the human immune system in the give-and-take of the natural disease process.

A genome is the totality of genetic material in the DNA of a particular organism. Genomes differ greatly in size and sequence across different organisms. Obtaining the complete genome sequence of a microbe provides crucial information about its biology, but it is only the first step toward understanding a microbe's biological capabilities and modifying them, if needed, for agricultural purposes.

Microbial biotechnology, enabled by genome studies, will lead to breakthroughs such as improved vaccines and better disease-diagnostic tools, improved microbial agents for biological control of plant and animal pests, modifications of plant and animal pathogens for reduced virulence, development of new industrial catalysts and fermentation organisms, and development of new microbial agents for bioremediation of soil and water contaminated by agricultural runoff.

Microbial genomics and microbial biotechnology research is critical for advances in food safety, food security, biotechnology, value-added products, human nutrition and functional foods, plant and animal protection, and furthering fundamental research in the agricultural sciences.

NIFA has identified four major related research objectives:

Assure that the complete nucleic acid sequences of high priority beneficial and detrimental agricultural microorganisms are available in public databases.

Assure that the agricultural research community has adequate resources and facilities available for the functional analysis of agricultural microbes (for example, expression array technologies, proteomics, relational databases, and other bioinformatics tools) so that practical benefits are not delayed.

Support training and extension for microbial genomics and its evolving technologies.

Foster U.S. interests through national and international public and private partnerships in microbial genomics, and, through such partnerships, facilitate capacity development in the United States and abroad that ensures public access and appropriate use of intellectual property.

Microbial biotechnology has a variety of useful applications in agriculture.

Assessing and managing environmental risks from transgenic microorganisms is an important issue for which scientists have developed research needs and priorities.

The mapping of microbial genomes is a key technology to understanding microorganisms and devising ways to improve their use in agricultural production, food safety, and bio-based chemicals. For more, see the Microbial Genomics program page.

23)Fermentation Biotechnology: principles, processes and products A general definition of fermentation is an energy-yielding anaerobic metabolic process in which organisms convert nutrients (typically carbohydrates) to alcohols and acids (lactic acid and acetic acid).

The most commonly known definition for fermentation is the conversion of sugar to alcohol, using yeast, under anaerobic conditions, as in the production of beer or wine, vinegars and cider. 

However, in biotechnology, the term is used more loosely to refer to growth of microorganisms on food, under either aerobic or anaerobic conditions.

Fermentation tanks, also called bioreactors, used for industrial fermentation processes are glass, metal or plastic tanks, equipped with gages and settings to control aeration, stir rate, temperature, pH and other parameters of interest. Units can be small enough for bench-top applications (5-10 L) or up to 10,000 L in capacity for large-scale industrial applications. Fermentation units such as these are used in the pharmaceutical industry for the growth of specialized pure cultures of bacteria, fungi and yeast, and the production ofenzymes and drugs.

Microbial fermentations may be classified into the following major

group^:^

(i) Those that produce microbial cells (biomass) as the product.

(ii) Those that produce microbial metabolites.

(iii) Those that produce microbial enzymes.

(iv) Those that modify a compound which is added to the fermenta-

tion - the transformation processes.

(v) Those that produce recombinant products.

Before the fermentation is started the medium must be formulated and sterilized, the fermenter sterilized, and a starter culture must be available in sufficient quantity and in the correct physiological state to inoculate the production fermenter. Downstream of the fermenter the product has to be purified and further processed and the effluents produced by the process have to be treated.