Title |
Kinetic characterization of laccase from Bacillus atrophaeus, and its potential in juice clarification in free and immobilized forms |
Author |
Lokesh Kumar Narnoliya1, Neera Agarwal1,2, Satya N. Patel1,2, and Sudhir P. Singh*1 |
Address |
1Center of Innovative and Applied Bioprocessing, S.A.S. Nagar, Mohali-140 306, India, 2Panjab University, Chandigarh, India |
Bibliography |
Journal of Microbiology, 57(10),900–909, 2019,
|
DOI |
10.1007/s12275-019-9170-z
|
Key Words |
laccase, Bacillus atrophaeus, immobilization, magnetic
nanoparticles, fruit juice clarification |
Abstract |
In the present study, a laccase gene (BaLc) from a lignin degrading
bacterium, Bacillus atrophaeus, has been cloned
and expressed in Escherichia coli. The optimal catalytic activity
of the protein was achieved at 5.5 pH and 35°C temperature,
measured by oxidation of ABTS. The Km and Vmax
values were determined as 1.42 mM and 4.16 μmole/min, respectively.
To achieve the enzyme recovery, the biocatalyst
(BaLc) was covalently attached onto the functionalized iron
magnetic-nanoparticles. The nanoparticles were characterized
by zeta-potential and FTIR analyses. The immobilized BaLc
enzyme was physico-kinetically characterized, exhibiting retention
of 60% of the residual activity after ten reaction cycles
of ABTS oxidation. The immobilized biocatalyst system was
tested for its biotechnological exploitability in plant juice
processing, achieving 41–58% of phenol reduction, 41–58%
decolorization, 50–59% turbidity reduction in the extracts of
banana pseudo-stem and sweet sorghum stalk, and apple fruit
juice. This is the first study to demonstrate the use of nanoparticle-
laccase conjugate in juice clarification. The findings
suggest that B. atrophaus laccase is a potential catalytic tool
for plant juice bioprocessing activities. |