The
Right Conditions
APPLICATION
PARAMETERS
The economical use of enzymes depends not only upon the mode of action in which the enzymes perform, but the characteristics that are exhibited by those enzymes acting in the presence of substrate. The following data concerns these commercial hydrolytic enzymes. These information is provided to allow these products to be more effectively applied.
pH
FACTOR
The most commonly encountered criterion for the selection of microbial-enzyme products is the pH at which these cultures perform. This activity is measured by
adjusting the pH of a solution containing a specific enzyme along with the substrate on which the enzyme acts and then measuring the rate at which the enzyme acts at one
given temperature.
The following diagram is a graphical representation of the pH range of activity of bacterial amylase. Amylase is the enzyme which catalyzes the breakdown of starch molecules into
dextrin as well as simple sugars such as dextrose (glucose) and maltose. As can be readily seen in this graph, the pH range of activity for this particular enzyme type is fairly broad, extending from pH 4.0 to over 8.5.
In the broad classification of proteases or protein digesting enzymes, there is even a greater degree of variability than with
amylases. There are two distinct proteases
produced in extra cellular form by these fungi. One of the proteases is commonly known as fungal neutral protease (FNP) and one is known as fungal acid protease
(FAP). These proteases not only vary drastically as to their effectiveness at varying pH values, but also the
FAP remains extremely active even when exposed to values in the pH 3.0 - pH 6.0 range.
Stability is another characteristic of enzymes which is important to the user of bacterial enzyme products. Most enzymes are very stable when kept dry, however in working solutions of high moisture situations,
stability can become a concern. Small amount of calcium ions usually stabilize enzymatic preparations to a great degree. Assuming that the enzyme is in presence solution with suitable amount' of calcium or other
stabilizing agent and in the presence of substrate to catalyze, there are two physicochemical conditions which immediately affect enzyme stability. One is pH and the other is
temperature. The following graph reveal the effects of changing pH on the stability of the two enzyme.
The next diagram shows the protease activity of fungal acid protease and fungal nelt protease
at various pH values.
TEMPERATURE
Temperature is the second condition which
greatly affects the stability of longevity of enzymes in moist conditions. The diagram
immediately below indicates the denaturing
effects of temperatures in the 65° Celcius (149° Fahrenheit) range upon
FAP. These Enzymes have only to encounter these temperatures for minutes for the indicated degree of activity loss to occur.
In contrast to this inherent heat liability
by fungal enzymes, the relative stability to high temperatures of bacterial enzymes is
indicated in the following graph.
As can easily seen from the
diagram,
denaturing effects are really a temperature/time combination effect, however the graph
indicates that bacterial amylase is quite stable for even an hour at 65° C and over half survives temperatures of even an hour at 75° C (167°
Fahrenheit). This can be important during high temperature
operations.
SUMMARY
In a biological waste treatment system, each enzyme is dependent upon the pH; temperature and other physicochemical
conditions of the system in which the enzyme preparation is working. To effectively utilize
the NS Series products, these parameters, must be fully understood for optimum effects, and results.
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