title: Microbial biomass in compost during colonization of Agaricus bisporus.
abstract: Agaricus bisporus mushrooms are commercially produced on a microbe rich compost. Here, fungal and bacterial biomass was quantified in compost with and without colonization by A. bisporus. Chitin content, indicative of total fungal biomass, increased during a 26-day period from 576 to 779 nmol N-acetylglucosamine g-1compost in the absence of A. bisporus (negative control). A similar increase was found in the presence of this mushroom forming fungus. The fungal phospholipid-derived fatty acid (PLFA) marker C18:2ω6, indicative of the living fraction of the fungal biomass, decreased from 575 to 280 nmol g-1compost in the negative control. In contrast, it increased to 1200 nmol g-1compost in the presence of A. bisporus. Laccase activity was absent throughout culturing in the negative control, while it correlated with the fungal PLFA marker in the presence of A. bisporus. PLFA was also used to quantify living bacterial biomass. In the negative control, the bacterial markers remained constant at 3000-3200 nmol PLFA g-1compost. In contrast, they decreased to 850 nmol g-1compost during vegetative growth of A. bisporus, implying that bacterial biomass decreased from 17.7 to 4.7 mg g-1compost. The relative amount of the Gram positive associated PLFA markers a15:0 and a17:0 and the Gram negative PLFA associated markers cy17:0 and cy19:0 increased and decreased, respectively, suggesting that Gram negative bacteria are more suppressed by A. bisporus. Together, these data indicate that fungal biomass can make up 6.8% of the compost after A. bisporus colonization, 57% of which being dead. Moreover, results show that A. bisporus impacts biomass and composition of bacteria in compost.
authors.affiliation: Department of Microbiology, Department of Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
authors.forename: Aurin M
authors.initials: AM
authors.lastname: Vos
authors.affiliation: Biometris, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands.
authors.forename: Amber
authors.initials: A
authors.lastname: Heijboer
authors.affiliation: Koninklijk Nederlands Instituut voor Onderzoek der Zee, Korringaweg 7, 4401 NT, Yerseke, The Netherlands.
authors.forename: Henricus T S
authors.initials: HTS
authors.lastname: Boschker
authors.affiliation: Somycel S.A-Sylvan, Z.I. Sud, Route de Tours, 37130, Langeais, France.
authors.forename: Barbara
authors.initials: B
authors.lastname: Bonnet
authors.affiliation: Department of Microbiology, Department of Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
authors.forename: Luis G
authors.initials: LG
authors.lastname: Lugones
authors.affiliation: Department of Microbiology, Department of Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands. h.a.b.wosten@uu.nl.
authors.forename: Han A B
authors.initials: HAB
authors.lastname: Wösten
keywords: Agaricus bisporus; Basidiomycete; Compost; Fungi; Microbial biomass; Mushroom