Abstract
After 2-3 flushes of Agaricus bisporus mushroom production, champost still contains about
50% of the carbohydrates and 45% of the lignin originally present in compost. Increased
uptake of the unused pool of polysaccharides may increase mushroom yield. Lignin is
removed during the vegetative growth phase of A. bisporus (phase III) but less efficiently
during mushroom formation (phase IV). Here, we overexpressed the manganese peroxidase
gene mnp1 in A. bisporus by placing it under control of the actin promoter to improve the
removal of lignin, thereby promoting accessibility of hemicellulose and cellulose.
Transformants produced MnP activity in liquid malt extract while the wild type strain did not.
MnP activity was 3-4 fold increased in wheat bran medium. During a semi-commercial
production cycle, MnP activity per gram wet compost was increased significantly at the end
of phase III (30%) while the activity was similar to the wild type strain at the initiation of
mushroom formation in phase IV. This indicates that other factors than mRNA accumulation
may be limiting in MnP1 production at this stage. After the 1st and 2nd flush, MnP activity
was increased 3-4 fold. There was no difference in mushroom yield or biomass formation in
compost as measured by chitin release. In addition, carbohydrates released after enzymatic
treatment of milled compost and carbohydrate content was not affected. Finally, lignin was
not affected differently by the mnp1 overexpressor as determined by pyrolysis. Efficient MnP
activity in compost may have been impaired by cofactor limitation.
50% of the carbohydrates and 45% of the lignin originally present in compost. Increased
uptake of the unused pool of polysaccharides may increase mushroom yield. Lignin is
removed during the vegetative growth phase of A. bisporus (phase III) but less efficiently
during mushroom formation (phase IV). Here, we overexpressed the manganese peroxidase
gene mnp1 in A. bisporus by placing it under control of the actin promoter to improve the
removal of lignin, thereby promoting accessibility of hemicellulose and cellulose.
Transformants produced MnP activity in liquid malt extract while the wild type strain did not.
MnP activity was 3-4 fold increased in wheat bran medium. During a semi-commercial
production cycle, MnP activity per gram wet compost was increased significantly at the end
of phase III (30%) while the activity was similar to the wild type strain at the initiation of
mushroom formation in phase IV. This indicates that other factors than mRNA accumulation
may be limiting in MnP1 production at this stage. After the 1st and 2nd flush, MnP activity
was increased 3-4 fold. There was no difference in mushroom yield or biomass formation in
compost as measured by chitin release. In addition, carbohydrates released after enzymatic
treatment of milled compost and carbohydrate content was not affected. Finally, lignin was
not affected differently by the mnp1 overexpressor as determined by pyrolysis. Efficient MnP
activity in compost may have been impaired by cofactor limitation.
| Original language | English |
|---|---|
| Title of host publication | Mushroom Science XIX |
| Subtitle of host publication | Proceedings of the XIXth international congress on the science and cultivation of edible fungi, Amsterdam, The Netherlands, 30 May-2 June 2016 |
| Editors | J.J.P. Baars, A.S.M. Sonnenberg |
| Publisher | International Society for Mushroom Science (ISMS) |
| Pages | 347-349 |
| ISBN (Electronic) | 9789090297712 |
| Publication status | Published - 2016 |
| Event | IXXth International Congress on the science and cultivation of edible and medicinal fungi - Amsterdam, Netherlands Duration: 30 May 2016 → 2 Jun 2016 |
Conference/symposium
| Conference/symposium | IXXth International Congress on the science and cultivation of edible and medicinal fungi |
|---|---|
| Country/Territory | Netherlands |
| City | Amsterdam |
| Period | 30/05/16 → 2/06/16 |