Single cell protein production is at the peak of infancy today. The production of single cell proteins can be accelerated by genetically modifying the micro-organisms employed for the purpose according to the need. The novel nature of SCP has made its demand to increase progressively over the years. The strategy behind SCP production not only decreases the risks that can be caused by waste accumulation but also proposes use for such waste that can be effectively useful to mankind.

Due to acute food shortage occurring in nature, researchers are rapidly developing new alternative for food consumption. SCP production from yeast, bacteria or fungi has made it easier to deal with the issue at hand. A recent breakthrough in this field by Dharumadurai DHANASEKARAN et al. points towards the production SCP from pineapple waste. Pineapple is a fruit crop that belongs to the family Bromeliaceae. It is grown in large quantities in the researchers' native country India, with over 100 varieties comprising 24,350 to 56,000 hectare of land. For the production, yeast strains were employed. Increase in pineapple waste concentration lead to increase in biomass concentration. The use of reducing sugar was found to have increased with the increase in concentration of the substrates. This finding have successfully revealed that pineapple waste can be used as a strong source of carbon for SCP Production.

Single Cell Protein is the mixed protein content obtained by drying the cells of micro-organisms and is widely abbreviated as SCP. They can be used as both animal feed and human food supplement. SCP is obtained from the cultures of micro-organisms like bacteria, fungi, yeast or algae grown on a subsequent amount of biomass which generally includes agricultural or other types of wastes (e.g. sewage waste).

COMPOSITION FUNGI ALGAEYEAST
Protein 30-40% 40-60% 45-55%
Fat9-14%8-10%5-10%
Nucleic Acid7-10%3-8%6-12%


SCP production is achieved in five major steps. These include Selection of the strain, Fermentation, Harvesting, Post-harvesting Treatment and SCP Processing for food consumption. Each step is important and ensures the successful production of SCP in consumable condition. Selection of a strain is the first and the most critical step in the production of SCP since it the quality and yield of the protein totally depends on the type of microbe employed. Also, the possible harmful effects of the selected strain should be analyzed so that the produce protein do not produce any toxic or undesirable effects in the consumer, be it a human or an animal. This step is carried out in fermenters that provide facilities for aeration and temp, pH controls. Other than fermenters, it can also be carried out in trenches or ponds. Fed-batch cultures are used for the microbes and typically, deep-lift or air-lift fermenters are preferred for fermentation. When the colonies of microbes are fully grown they are harvested by a process known as decantation in which a bulk of cells is removed from the batch. After harvesting the cells are subjected to a variety of purposes like drying, washing, separation by centrifugation etc. (reverse order). The SCP obtained so far is further processed in order to make it consumable. First of all, the cell wall of the achieved cell lines is broken since it is indigestible. There are a lot of methods available to achieve this object. Some mechanical methods include crushing, crumbling, grinding, pressure homogenization, etc. Enzymes (nuclease enzymes) or salts (NaCl, Sodium dodecyl sulfate) can be used as well to either digest or disrupt the cell wall. Physical methods include heating, drying, freeze-thaw and osmotic shock.

After disruption of the cell wall, the nucleic acid content is attempted to be reduced. To achieve this, chemicals and enzymatic treatments are preferred that include chemical treatment with alcohol, acid, alkalis, salts and enzymatic treatment with ribonuclease and nuclease. Although use of these chemicals may lead to the formation of lygino-alanine causing hypersensitivity reactions in skin.

Figure 1 Steps in SCP Production.



Though many strategies are already present, constant search for new and improved methods is always on. The use of pineapple waste or extracts would prove to be a successful strategy for the still developing economy of India since this fruit is found in abundance in the country of India. Serious consideration should be given to the use of microbial biomass and waste as substrate for SCP production due to the huge lack of food supplements and significantly high protein contents present in micro-organisms.

By opting these methods and proposing new and improved strategies that allow maximum consumption of waste materials as substrates, we can ensure a better future of the food sector. SCP has significantly contributed to the human economy and has increased alternatives for better food supplementation and less exploitation of natural resources. With the increasing developments, we can sincerely hope for novel and better products coming to the markets soon.

About Author / Additional Info: