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−1 compost 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−1 compost in the negative control. In contrast, it increased to 1200 nmol g−1 compost 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−1 compost. In contrast, they decreased to 850 nmol g−1 compost during vegetative growth of A. bisporus, implying that bacterial biomass decreased from 17.7 to 4.7 mg g−1 compost. 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.Electronic supplementary materialThe online version of this article (doi:10.1186/s13568-016-0304-y) contains supplementary material, which is available to authorized users.

Growing edible mushrooms: a conversation between bacteria and fungi

“…MGP may also serve as a direct source of nutrients for fungi that produce bacteriolytic enzymes. Agaricus bisporus has been postulated to feed on compost bacteria since bacterial biomass was noted to decrease about fourfold during the cropping trial when analysing the phospholipid fatty acid content (Vos et al ., ). As reported, A. bisporus appears to degrade B. subtilis and was able to grow employing dead B. subtilis as the sole carbon and nitrogen source (Fermor and Wood, ; Fermor et al ., ).…”

“…Bacteria in turn benefit from enhanced dispersal and growth on fungal exudates (Warmink and Van Elsas, ). However, fungi may also consume bacteria and assimilate bacterial carbon and nitrogen as a nutrient source (Vos et al ., ; Kertesz and Cai, ); whereas bacteria can cause significant yield losses by causing a wide range of mushroom diseases (Frey‐Klett et al ., ; Gea and Navarro, ).…”

“…A wide variety of interactions between bacteria and cultivated mushrooms has been described leading to both positive and negative outcomes for the fungus, depending on the bacterial isolate and the developmental stage of the fungus (Frey-Klett et al, 2011). The benefits for fungi of forming mutualistic associations with bacteria include the action of helper bacteria in promoting ectomycorrhizal association with plant symbionts, enhanced nutrition through degradation of complex poly-carbohydrates by lignocellulosic enzyme activity, the consumption of volatile organic compounds (VOCs) blocking mushroom fructification by bacteria and secretion of antibiotics to suppress competing fungi or provide protection against crop parasites (Sbrana et al, 2002;Pion et al, 2013;Pudelko, 2014;Antunes et al, 2016;Vos et al, 2017;Pandin et al, 2018a,b). Bacteria in turn benefit from enhanced dispersal and growth on fungal exudates (Warmink and Van Elsas, 2009).…”

<b>Recycling of the biomass waste defatted almond meal as a novel nutritional supplementation for cultivated edible mushrooms

“…There is controversy regarding the nutrient content within supplements used for mushroom growing. In mushroom compost, wheat straw in the major carbon source while chicken litter is the major nitrogen source, but frequently the colonized compost (Phase III compost used for A. bisporus cultivation) is supplemented with sterile protein rich nutrients (Vos et al, 2017). According to Arce-Cervantes et al (2015), A. bisporus needs a simultaneous source of oil and protein in order to increase yields, and that with a source of polysaccharides it is possible to formulate a supplement equivalent to the traditional one based on crushed soybeans (25% protein and 18% oil).…”

Mycelia growth performance of Agaricus bisporus in culture media of composts supplemented with Sesbania sesban straw and phosphate rock

“…This phenomenon appears because of the compositions of WCS1 compost which have a high percentage of Egyptian pea (Sesbania sesban) straw which is rich in nitrogen content compared with the wheat straw (Table 1). This straw leads to the best microbial growth that reflects on biomass of compost and finally on the nitrogen content in WCS1 and WHS1 composts compared with the control during composting processes (Vos et al 2017).…”