✦ LIBER ✦

Dimethylsulfoxide elevates extracellular laccase (phenol oxidase) activity of Pycnoporus cinnabarinus grown on a low nutritional newspaper medium

✍ Scribed by Cameron L Jones; Warren L Baker; Greg T Lonergan

Book ID: 102314434
Publisher: Wiley (John Wiley & Sons)
Year: 2001
Tongue: English
Weight: 170 KB
Volume: 76
Category: Article
ISSN: 0268-2575
DOI: 10.1002/jctb.400

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✦ Synopsis

Abstract

The white‐rot fungus Pycnoporus cinnabarinus, grown on a low nutrient newspaper medium, secreted low amounts of extracellular laccase. The laccase activity was increased when 3% methanol was added to the medium and further increased when 3% dimethylsulfoxide was added. Dimethylsulfoxide increased the enzyme activity over controls when the fungus was grown on a malt extract broth, or media containing either recycled Kraft paper or cellobiose. Treatment with the ionophore A23187 suggested that dimethylsulfoxide acted as a paramorphogen to increase the branch points of the mycelial mat. Hence, the number of ion channels for secretion of the enzyme was increased. When the fungus was grown in a 2 dm^3^ bioreactor, sparged with air, the measured extracellular protein concentration rose and remained relatively steady for 15 days. The enzyme activity and specific activity reached a maximum between days 6 and 9 and then fell from day 10 of fermentation. The presence of dimethylsulfoxide in the bioreactor caused a four‐fold increase in enzyme activity and prolonged its secretion in the bioreactor for at least 25 days. The protein concentration and specific activity also remained at high levels over this period.