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In JoVE (1)
Other Publications (3)
Articles by Jonathan S. Schilling in JoVE
JoVE General
Agar-Block Microcosms for Controlled Plant Tissue Decomposition by Aerobic Fungi
Department of Bioproducts and Biosystems Engineering, University of Minnesota
This video demonstrates a controlled environment approach to study degradation of lignocellulosic plant tissues by aerobic fungi. The ability to control nutrient sources and moisture is a key advantage of agar-block microcosms, but the approach often yields mixed success. We address critical pitfalls to yield reproducible, low-variability results.
Other articles by Jonathan S. Schilling on PubMed
Metal Accumulation Without Enhanced Oxalate Secretion in Wood Degraded by Brown Rot Fungi
Brown rot fungi were incubated in agar and agar-wood microcosms containing metallic or hydroxide forms of Al, Cu, and Fe. Metal dissolution was associated with elevated oxalate concentrations in agar, but metals translocated into wood did not affect oxalate accumulation, crystal production, or decay rate, demonstrating a substrate-dependent oxalate dynamic.
Synergy Between Pretreatment Lignocellulose Modifications and Saccharification Efficiency in Two Brown Rot Fungal Systems
Brown rot wood-degrading fungi distinctly modify lignocellulose and completely hydrolyze polysaccharides (saccharification), typically without secreting an exo-acting glucanase and without removing lignin. Although each step of this two-step approach evolved within the same organism, it is unknown if the early lignocellulose modifications are made to specifically facilitate their own abbreviated enzyme system or if enhancements are more general. Because commercial pretreatments are typically approached as an isolated step, answering this question has immense implication on bioprocessing. We pretreated spruce and pine blocks with one of two brown rot fungi, Gloeophyllum trabeum or Fomitopsis pinicola. Wood harvested at weeks 1, 2, 4, and 8 showed a progression of weight loss from time zero due to selective carbohydrate removal. Hemicellulose losses progressed faster than cellulose loss. This "pretreated" material was then saccharified with commercially relevant Trichoderma reesei cellulases or with cellulases from the brown rot fungi responsible for degrading the wood to test for synergy. With increased decay, a significant increase in saccharification efficiency was apparent but not limited to same-species enzyme sources. We also calculated total sugar yields, and calculations that compensate for sugars consumed by fungi suggest a shorter residence time for fungal colonization than calculations based solely on saccharification yields.
Competition Between Two Wood-degrading Fungi with Distinct Influences on Residues
Many wood-degrading fungi colonize specific types of forest trees, but often lack wood specificity in pure culture. This suggests that wood type affects competition among fungi and indirectly influences the soil residues generated. While assessing wood residues is an established science, linking this information to dominant fungal colonizers has proven to be difficult. In the studies presented here, we used isolate-specific quantitative PCR to quantify competitive success between two distinct fungi, Gloeophyllum trabeum and Irpex lacteus, brown and white rot fungi, respectively, colonizing three wood types (birch, pine, oak). Ergosterol (fungal biomass), fungal species-specific DNA copy numbers, mass loss, pH, carbon fractions, and alkali solubility were determined 3 and 8 weeks postinoculation from replicate wood sections. Quantitative PCR analyses indicated that I. lacteus consistently outcompeted G. trabeum, by several orders of magnitude, on all wood types. Consequently, wood residues exhibited distinct characteristics of white rot. Our results show that competitive interactions between fungal species can influence colonization success, and that this can have significant consequences on the outcomes of wood decomposition.
