21-09-2012, 12:12 PM
ISOLATION, CHARACTERISATION,OPTIMIZATION, AND PRODUCTION
OF YEAST ( SCP) ON MUSTARD OILCAKE
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INTRODUCTION
Single-cell proteins are the dried cells of microorganism, which are used as protein supplement in human foods or animal feeds. Microorganisms like algae, fungi, yeast and bacteria, utilize inexpensive feedstock and wastes as sources of carbon and energy for growth to produce biomass, protein concentrate or amino acids. Since protein accounts for the quantitatively important part of the microbial cells, these microorganisms, also called single cell protein as natural protein concentrate. With increase in population and worldwide protein shortage the use of microbial biomass as food and feed is more highlighted. Although single cell protein has high nutritive value due to higher protein, vitamin, essential amino acids and lipid content, there is a doubt to be replaced to the conventional protein sources due to their high nucleic acid content and slower in digestibility.
SCP production technologies arose as a promising way to solve the problem of worldwide protein shortage. They evolved as bioconversion processes which turned low value by-products, often wastes, into products with added nutritional and market value. Intensive research into fermentation science and technology for biomass production, as well as feeding, has resulted in a profound body of knowledge, the benefits of which now span far beyond the field of SCP production. The widespread application of plant breeding programmes and agricultural crop production techniques resulted in a high availability of plant food sources, such as soya, maize, wheat and rice in the second half of the 20th century. In addition, political and economic developments, which swayed the world order from a system of blocks to globalization, facilitated the open trade of agricultural products. These agricultural products out marketed SCP on the grounds of lower price.
HISTORY
The pioneering research conducted almost a century ago by Max Delbruck and his colleagues at the Institute fu rGärungsgewerbe in Berlin first highlighted the value of surplus brewer’s yeast as a feeding supplement for animals [1]. This experience proved more than useful in the ensuing First World War, when Germany managed to replace as much as half of its imported protein sources by yeast. Since brewer’s yeast from beer production was not produced in sufficient quantity to meet the demands as a protein feed, a very large proportion of yeast biomass was expressly produced by aerobic fermentations in a semi defined medium containing ammonium salts as the nitrogen source [2]. This methodology was more efficient than brewing, but still resulted in some fermentation of the carbohydrate source, and suboptimal yield of biomass obtained per unit of substrate.
In 1919, a process was invented by Sac in Denmark and Hayduck in Germany in which sugar solution was fed to an aerated suspension of yeast instead of adding yeast to a diluted sugar solution [3]. This process was known as ‘Zulaufverfahren’. An incremental-feeding or fed-batch process was thus born which is still successfully used in today’s fermentations.
After the end of World War I, German interest in fodder yeast declined, but was revived around 1936 by the ‘Heeresverwaltung’, when both brewer’s yeast, and a variety of yeast specially mass cultured, were used to supplement human and animal diets. By then the advantages of aerobic production of baker´s yeast in a richwort had been fully recognized as a rapid means of producing food in large scale industrial installations. A radically different concept to that of agricultural production [4].Around this time, the nutritive value of yeast was also the intense subject of study, with two important books published [5, 6].
Why scp
The increasing world population has resulted in a rising demand for protein for human consumption and animal production. The demand for protein is certain to become more serious with over exploitation of the sea and the depletion of most of the available arable land with the ever rapid population growth. There is, therefore, the need to find; new protein sources whose productionwould require less of the agricultural land, with lower production cost (Israelidis and Conduonis, 1982). Aquaculture has been suggested as a veritable means of bridging the protein demand supply gap. However, this production system can only be effective if operated as an enterprise. In developing countries like Nigeria, the development of aquaculture has been hindered by the prohibitive cost of commercial aqua feeds. Aqua feeds have high protein content and this tends to increase the cost of production, especially with the high inclusion level of fishmeal. It has thus become imperative to search out for cheaper alternative protein sources to fish meal.
According to who, the child is going on malnutrition of protein. There are many source of protein but poor man can’t effort and their child suffered from malnutrion of protein. Due to malnutrition of protein the child has poor growth of physical and mental and their life span narrow.SCP is the alternative way to provide protein to child and scp is cheaper than other protein sources and it is easily effort by a poor man, the production cost of scp is very low and it become cheaper than other protein sources. Yeast and other microorganism are used to produce scp .these microorganism easily grow on carbon and nitrogen .so scp is the best alternative source of protein to overcome the problem of protein in diet.