Background:
Tannases are enzymes with biotechnological potential produced mainly by microorganisms as
filamentous fungi. In this context, the production and characterization of a multi-tolerant tannase from
Aspergillus carbonarius
is described.
Results:
The filamentous fungus
A. carbonarius produced high levels of tannasewhen cultivated under solid-state
fermentation using green tea leaves as substrate/carbon source and tapwater at a 1:1 ratio as the moisture agent
for 72 h at 30°C. Two tannase activity peakswere obtained during the purification step usingDEAE-Cellulose. The
second peak (peak II) was purified 11-fold with 14% recovery from a Sepharose CL-6B chromatographic column.
The tannase frompeak II (tannase II)was characterized as a heterodimeric glycoprotein of 134.89 kDa, estimated
through gel filtration,with subunits of 65 kDa and 100 kDa, estimated through SDS-PAGE, and 48% carbohydrate
content. The optimal temperature and pH for tannase II activity was 60°C and 5.0, respectively. The enzyme was
fully stable at temperatures ranging from 20–60°C for 120 min, and the half-life (T
1/2) at 75°C was 62 min. The
activation energy was 28.93 kJ/mol. After incubation at pH 5.0 for 60 min, 75% of the enzyme activity was
maintained. However, enzyme activity was increased in the presence of AgNO
3 and it was tolerant to solvents
and detergents. Tannase II exhibited a better affinity for methyl gallate (Km = 1.42 mM) rather than for tannic
acid (Km = 2.2 mM).
Conclusion:
A. carbonarius tannase presented interesting properties as, for example, multi-tolerance, which
highlight its potential for future application.
