Screening for novel laccase-producing microbes.
OBJECTIVE
To discover novel laccases potential for industrial applications.


RESULTS
Fungi were cultivated on solid media containing indicator compounds that enabled the detection of laccases as specific colour reactions. The indicators used were Remazol Brilliant Blue R (RBBR), Poly R-478, guaiacol and tannic acid. The screening work resulted in isolation of 26 positive fungal strains. Liquid cultivations of positive strains confirmed that four efficient laccase producers were found in the screening. Biochemical characteristics of the four novel laccases were typical for fungal laccases in terms of molecular weight, pH optima and pI. The laccases showed good thermal stability at 60 degrees C.


CONCLUSIONS
Plate-test screening based on polymeric dye compounds, guaiacol and tannic acid is an efficient way to discover novel laccase producers. The results indicated that screening for laccase activity can be performed with guaiacol and RBBR or Poly R-478.


CONCLUSIONS
Laccases have many potential industrial applications including textile dye decolourization, delignification of pulp and effluent detoxification. It is essential to find novel, efficient enzymes to further develop these applications. This study showed that relatively simple plate test screening method can be used for discovery of novel laccases.
VTT Biotechnology, Espoo, Finland.
L-L
LL
Kiiskinen
M
M
Rättö
K
K
Kruus
D000880:Anthraquinones; D004396:Coloring Agents; D003470:Culture Media; D005658:Fungi / Q000201:enzymology / Q000302:isolation & purification*; D006139:Guaiacol; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D007218:Industrial Microbiology; D042845:Laccase / Q000096:biosynthesis*; D008970:Molecular Weight; D011108:Polymers; D013634:Tannins; D013696:Temperature
D000880:Anthraquinones; D004396:Coloring Agents; D003470:Culture Media; D007202:Indicators and Reagents; D011108:Polymers; D013634:Tannins; C017971:poly R-478; D006139:Guaiacol; D042845:Laccase; C024758:Remazol Brilliant Blue R