326
fungi acidic pH for best growth and mannanase production (Mabrouk and El
Ahwany 2008; Abdeshahian et al. 2010).
The most potent mannanase producer was reported to be Aspergillus niger, which
produced the highest extracellular mannanase activity (2.90 U/mL), followed by
Aspergillus flavus (2.54 U/mL) and Aspergillus ochraceous (2.16 U/mL). The optimal operating conditions for β-mannanase activity by Aspergillus niger arising from
this study are as follows: temperature of 30 °C, 6 days incubation period, initial pH
5.0 and inoculum size of 3 × 10
6
spore/mL (Alsarrani 2011). In another study mannanase production was carried out with Aspergillus siydowii grown on 1.0% (w/v)
banana stem as the carbon source, producing 1.229 U mL
−1
, and Emericella nidulans grown on 1.0% (w/v) dirty cotton residue producing 0.455 U mL
−1
of mannanase activity. Fermentation was conducted using as inoculum 108 spores mL
−1
during 7 days and agitation of 120 rpm (de Siqueira et al. 2010).
Heck et al. (2005) optimized the mannanase production by Bacillus circulans in
SSF using industrial fibrous soy residue and nutritive solution in a 500 mL cylindrical bioreactor achieving 0.54 U mg
−1
. Bacteria of Bacillus amyloliquefaciens produce the mannanase enzyme and the activity of the mannanase enzyme with a
substrate that is a combination of coconut and tofu waste is not much different
compared to with a substrate using locust bean gum, with only a 13.34% difference
and the optimum pH and temperature are the same. The results showed that the best
conditions were a substrate ratio of 80% coconut waste to 20% tofu waste, a 48 h
incubation time, a pH of 6.5 and a temperature of 40 °C yielding a mannanase enzymatic activity of 5.13 U mL
−1
. When locust bean gum was added to the substrate
composed of coconut and tofu waste, the best conditions were a dose of 0.6%, a
48 h incubation time, a pH = 6.5 and a temperature of 40 °C yielding a 5.92 U mL
–1
mannanase enzymatic activity (Zurmiati et al. 2017).
Safety of Exogenous Enzymes
Safety concerns associated with food enzymes in general are possible allergenic,
irritative and otherwise toxic properties. Oral toxicity is especially relevant to consumers of food enzymes. The regulation of enzymes internationally is quite varied
between countries, with specific country either requiring a full approval process, a
notification of enzyme or no requirement thereof. Pre-market approval may depend
on whether an enzyme is classified as processing aid or a food additive, though the
point of consideration regardless of classification is that the safety of the enzyme
must be assured. Challenges to regulators and industry arise from unresolved issues
and from lack of harmonization of both legislation and safety evaluation (Agarwal
and Sahu 2014).
In occupational contexts enzyme exposure includes mainly to dust or liquid aerosols that are set free while handling enzyme preparation in either manufacturing of
the enzyme itself or using enzyme preparations in other industrial contexts. This is
generally true for all enzymes regardless of the particular end-use. The particles are
S. Farooq et al.
fungi acidic pH for best growth and mannanase production (Mabrouk and El
Ahwany 2008; Abdeshahian et al. 2010).
The most potent mannanase producer was reported to be Aspergillus niger, which
produced the highest extracellular mannanase activity (2.90 U/mL), followed by
Aspergillus flavus (2.54 U/mL) and Aspergillus ochraceous (2.16 U/mL). The optimal operating conditions for β-mannanase activity by Aspergillus niger arising from
this study are as follows: temperature of 30 °C, 6 days incubation period, initial pH
5.0 and inoculum size of 3 × 10
6
spore/mL (Alsarrani 2011). In another study mannanase production was carried out with Aspergillus siydowii grown on 1.0% (w/v)
banana stem as the carbon source, producing 1.229 U mL
−1
, and Emericella nidulans grown on 1.0% (w/v) dirty cotton residue producing 0.455 U mL
−1
of mannanase activity. Fermentation was conducted using as inoculum 108 spores mL
−1
during 7 days and agitation of 120 rpm (de Siqueira et al. 2010).
Heck et al. (2005) optimized the mannanase production by Bacillus circulans in
SSF using industrial fibrous soy residue and nutritive solution in a 500 mL cylindrical bioreactor achieving 0.54 U mg
−1
. Bacteria of Bacillus amyloliquefaciens produce the mannanase enzyme and the activity of the mannanase enzyme with a
substrate that is a combination of coconut and tofu waste is not much different
compared to with a substrate using locust bean gum, with only a 13.34% difference
and the optimum pH and temperature are the same. The results showed that the best
conditions were a substrate ratio of 80% coconut waste to 20% tofu waste, a 48 h
incubation time, a pH of 6.5 and a temperature of 40 °C yielding a mannanase enzymatic activity of 5.13 U mL
−1
. When locust bean gum was added to the substrate
composed of coconut and tofu waste, the best conditions were a dose of 0.6%, a
48 h incubation time, a pH = 6.5 and a temperature of 40 °C yielding a 5.92 U mL
–1
mannanase enzymatic activity (Zurmiati et al. 2017).
Safety of Exogenous Enzymes
Safety concerns associated with food enzymes in general are possible allergenic,
irritative and otherwise toxic properties. Oral toxicity is especially relevant to consumers of food enzymes. The regulation of enzymes internationally is quite varied
between countries, with specific country either requiring a full approval process, a
notification of enzyme or no requirement thereof. Pre-market approval may depend
on whether an enzyme is classified as processing aid or a food additive, though the
point of consideration regardless of classification is that the safety of the enzyme
must be assured. Challenges to regulators and industry arise from unresolved issues
and from lack of harmonization of both legislation and safety evaluation (Agarwal
and Sahu 2014).
In occupational contexts enzyme exposure includes mainly to dust or liquid aerosols that are set free while handling enzyme preparation in either manufacturing of
the enzyme itself or using enzyme preparations in other industrial contexts. This is
generally true for all enzymes regardless of the particular end-use. The particles are
S. Farooq et al.