BACTERIA

Thousands of different types of bacteria exist everywhere in our world, and most of them carry on bacterial digestion in some way. However, some of them are found only in a particular environment and require specialised types of food, and / or have very unique biological roles.

A bacteria is a single cell life form - each individual cell is a separate, unique organism. Bacteria often grows into colonies that appear as jelly - like masses, but each cell remains an independent, individual life. Bacteria reproduce by a process called cell division. A mature bacteria reproduces by dividing into two "daughter" cells, each identical to each other and the parent bacteria. Under ideal conditions, bacteria can reproduce very rapidly, producing a new generation every 20 - 30 minutes.

Following this reproduction process, we see that the number of individual bacteria doubles with each generation. The population explodes as the number of organisms increase logarithmically. This population boom begins soon after the bacteria is introduced into a favourable environment, after a short lag time when the bacteria becomes acclimatised.

Obviously this population cannot increase forever. At some point, the food source will be depleted, waste products will accumulate, or some other change in the environment will cause the population to level off or decrease (such as a change in pH, temperature, or oxygen level of the environment.) Also, introduction of any poisons into the environment may have negative effects on the population,as well as competition from other types of bacteria.

Bacteria can be classified into different types: aerobic types, (which require oxygen to live) and anaerobic (which can live without oxygen). Facultative types can thrive under both aerobic and anaerobic condition.

(2) For waste digestion, we can identify several beneficial characteristics that we want our chosen bacteria to have. The "good" bacteria that we will choose must:
1. Digest waste quickly and completely, without producing significant odours or noxious gas.
2. Consume (digest) a wide variety of organic material that are present in wastes.
3. Grow and reproduce quickly and readily in the environmental conditions found in waste disposal systems.
4.. Not cause any disease in man or animals - they must be "nonpathogenic".

Certain bacteria belonging to the Bacillus species have these desirable characteristics. They consume organic waste thousands of times faster than the bacteria that are naturally present in the waste. They grow and reproduce easily, are nonpathogenic, and do not produce foul odours or gas as they digest waste.

These "good" bacteria are grown by artificial means on a liquid or dry nutrient medium. These cultured bacteria are then freeze dried to put them in a state of suspension. They remain alive, ready to swim, eat and reproduce as soon as they are activated and put into the proper environment.

The proper environment needed for a speedy growth and reproduction of these good bacteria must have the following characteristics:

1. Dissolved oxygen (for the aerobic types that require it) in sufficient quantities.
2. A water medium containing food (organic waste) for them to eat.
3. Moderate temperatures, between 10 deg.C and 40 deg.C.
4. Proper pH - not too acid nor too alkaline - between 6 & 9 on the pH scale.

ENZYMES

What is an enzyme? How does it aid digestion?

An enzyme is a catalyst that breaks up long, complex waste molecules into smaller pieces, which can then be digested directly by the bacteria.

Enzymes are simply chemicals - they are not living things, and they cannot grow or reproduce themselves. Enzymes are manufactured by bacteria, and used by the bacteria in order to digest waste. The extra enzymes that are mixed into digestant products are actually produced by special bacteria, extracted from them in dry form and blended into the digestant mixture.

Enzymes are added to digestants to help them go to work faster. When added to the organic waste, the enzymes immediately go to work breaking down the waste. The large complex, molecules of proteins, starches, carbohydrates and cellulose are broken into smaller, simpler pieces. These enzymes act like chemical "blades" chopping the large molecules of waste into smaller pieces of "prepared food" for the bacteria. The growing bacteria will then start to produce more enzymes on their own, creating a continuing cycle of enzyme production.

The following four types of enzymes are often incorporated into digestant products:
1. PROTEASE - breaks down proteins
2. LIPASE - breaks down fats and greases
3. CELLULASE - breaks down cellulose
4. AMYLASE - breaks down carbohydrates and starches

Enzymes are specific, so that one type of enzyme can work on only one type of molecule. Thus, protease enzyme will break down complex proteins into simple pieces, but will have no effect on fats and greases. Likewise, lipase will attack animal fats and grease, but will not work on paper or wood fibres (cellulose).

ESSENTIAL NUTRIENTS:
Special nutrients are added to create the vitamins and minerals required for the fastest growth and the greatest activity of the bacteria. These vitamins and minerals may not be present in the waste, and a lack of any one of them may seriously inhibit the growth, reproduction and waste digestion performance. They must be added to the digestant product to assure the fastest, most efficient digestant action.