Pestalotiopsis sp. J63

producing a high activity of laccase

is a new marine-derived fungus isolated from the oceanic sediment of the East China Sea. Since the marine environment is oligotrophic nutrient

marine derived fungi may use small amount of nutrients to grow and produce laccases. Agricultural residues that are mainly composed of lignin

cellulose and hemicellulose are difficult to be degraded and few microbes can take them as substrates

so they are considered as oligotrophic nutrient and have the potential to be used to produce value added products. In this study

the ability of Pestalotiopsis sp. J63 to use agricultural residues to produce laccases was tested in the submerged fermentation. The combination of 3 g·L

-1

maltose and 20 g·L

-1

rice straw was the best carbon sources and 8 g·L

-1

ammonium sulfate was the best nitrogen source under the condition without inducers. The effects of five inducers

the feeding time and concentration of inducer on laccase production were investigated. Adding 0.09 mmol·L

-1

phenol after 24 h of incubation led to high laccase activity (5089 U·L

-1

)

while with 0.09 mmol·L

-1

phenol in the medium and wheat br

an as the nitrogen source

the laccase activity could reach 5791.7 U·L

-1

. Native-PAGE results showed that two laccase isozymes were present in the cultures. One existed in both induced and non-induced culture filtrates

while the other was only found in the fermentation with the addition of phenol

guaiacol and veratryl alcohol.