Study of the production of lipase in SSF
In order to study the effect of moisture, concentration
of glucose and olive oil on lipase production in culture
medium where ammonium sulphate and urea were
used as nitrogen sources, the study was carried out
using the Box-Behnken experimental design.
Table 5 shows the maximum values of lipase activity
reached with each nitrogen source employed. It can
be observed that the highest value of activity was obtained
in the presence of the combination of ammonium
sulphate and urea. The optimum conditions of the medium
are presented in Table 6.
It is necessary to add 1.9 g of liquid (1.9 mL of liquid)
for each gram of dry solid substrate to obtain 65 %
of moisture. Therefore, 9.14 IU/g dss of lipase activity is
equivalent to 4.8 IU/mL.
Comparing the best results of lipase activity obtained
using both SmF and SSF, and expressed in terms of the
liquid volume of the culture medium, it can be concluded
that lipase activity produced by SSF (4.8 IU/mL)
is superior to the reported value for SmF (1.46 IU/mL).
For this reason it can be demonstrated that the lipase
obtained using SSF is more concentrated, making it
an attractive feature from an economic standpoint. Similar
criteria are shared by at least one other research
group relating to their work on lipase production by
Penicillium restrictum using SmF and SSF (16).