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Appl Environ Microbiol, July 1998, p. 2409-2417, Vol. 64, No. 7
Division of Wood Science,
Received 5 February 1998/Accepted 16 April 1998
Bjerkandera sp. strain BOS55 is a white rot fungus that
can bleach EDTA-extracted eucalyptus oxygen-delignified kraft pulp (OKP) without any requirement for manganese. Under manganese-free conditions, additions of simple physiological organic acids (e.g., glycolate, glyoxylate, oxalate, and others) at 1 to 5 mM stimulated brightness gains and pulp delignification two- to threefold compared to
results for control cultures not receiving acids. The role of the
organic acids in improving the manganese-independent biobleaching was
shown not to be due to pH-buffering effects. Instead, the stimulation
was attributed to enhanced production of manganese peroxidase (MnP) and
lignin peroxidase (LiP) as well as increased physiological
concentrations of veratryl alcohol and oxalate. These factors
contributed to greatly improved production of superoxide anion
radicals, which may have accounted for the more extensive biobleaching.
Optimum biobleaching corresponded most to the production of MnP. These
results suggest that MnP from Bjerkandera is purposefully produced in the absence of manganese and can possibly function independently of manganese in OKP delignification. LiP probably also
contributed to OKP delignification when it was present.
0099-2240/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
Role of Organic Acids in the Manganese-Independent
Biobleaching System of Bjerkandera sp. Strain
BOS55
*
Corresponding author. Mailing address: Division of
Industrial Microbiology, Department of Food Technology and Nutritional Sciences, P.O. Box 8129, Wageningen Agricultural University, 6700 EV
Wageningen, The Netherlands. Phone: 31-317-484976. Fax: 31-317-484978. E-mail: JIM.FIELD{at}ALGEMEEN.IM.FTNS.WAU.NL.
Appl Environ Microbiol, July 1998, p. 2409-2417, Vol. 64, No. 7
0099-2240/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
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