Summary: A fungal strain isolated from a microbial consortium growing in a natural asphalt lake is able to grow in purified asphaltenes as the only source of carbon and energy. The asphaltenes were rigorously purified in order to avoid contamination from other petroleum fractions. In addition, most of petroporphyrins were removed. The 18S rRNA and β‐tubulin genomic sequences, as well as some morphologic characteristics, indicate that the isolate is Neosartorya fischeri . After 11 weeks of growth, the fungus is able to metabolize 15.5% of the asphaltenic carbon, including 13.2% transformed to CO ₂ . In a medium containing asphaltenes as the sole source of carbon and energy, the fungal isolate produces extracellular laccase activity, which is not detected when the fungus grow in a rich medium. The results obtained in this work clearly demonstrate that there are microorganisms able to metabolize and mineralize asphaltenes, which is considered the most recalcitrant petroleum fraction.

The gut of insects is a productive environment for discovering undescribed species of yeasts, and the gut of wood-feeding insects of several families is especially rich in yeasts that carry out the fermentation of cellobiose and xylose. Passalid beetles (Passalidae, Coleoptera) live in dead wood that they ingest as their primary food source. We report the isolation, molecular identification and physiological characterization of 771 yeast cultures isolated from the gut of 16 species of passalids collected in nine localities in Guatemala. Ascomycete yeasts were present in the gut of every passalid studied, and the xylose-fermenting (X-F) yeasts Scheffersomyces shehatae and Scheffersomyces stipitis were the most abundant taxa isolated. The gut of the beetles also contained undescribed cellobiose-fermenting and X-F species in the Lodderomyces,Scheffersomyces and Spathaspora, and undescribed species in Sugiyamaella clades as well as rare yeast species in the Phaffomyces and Spencermartinsiella clades. Basidiomycete yeasts in the generaCryptococcus and Trichosporon were also common. The yeast species richness was influenced by the host species and the substrate, and gut-inhabiting yeasts have the ability to survive the differing physiological conditions of several gut compartments

Many of the known xylose-fermenting (X-F) yeasts are placed in the Scheffersomyces clade, a group of ascomycete yeasts that have been isolated from plant tissues and in association with lignicolous insects. We formally recognize fourteen species in this clade based on a maximum likelihood (ML) phylogenetic analysis using a multilocus dataset. This clade is divided into three subclades, each of which exhibits the biochemical ability to ferment cellobiose or xylose. New combinations are made for seven species of Candida in the clade, and three X-F taxa associated with rotted hardwood are described: Scheffersomyces illinoinensis (type strain NRRL Y-48827^T = CBS 12624), Scheffersomyces quercinus (type strain NRRL Y-48825^T = CBS 12625), and Scheffersomyces virginianus (type strain NRRL Y-48822^T = CBS 12626). The new X-F species are distinctive based on their position in the multilocus phylogenetic analysis and biochemical and morphological characters. The molecular characterization of xylose reductase (XR) indicates that the regions surrounding the conserved domain contain mutations that may enhance the performance of the enzyme in X-F yeasts. The phylogenetic reconstruction using XYL1 or RPB1 was identical to the multilocus analysis, and these loci have potential for rapid identification of cryptic species in this clade.

In 2010–2011, a Xylaria sp. was documented growing from seeds of both Chlorocardium rodiei and Chlorocardium venenosum, a commercially valuable timber in Guyana. We conducted extensive surveys in 2015–2016, where this Xylaria sp. was observed fruiting from ca. 80% of dispersed seeds in both natural and logged forests in the Upper Demerara-Berbice, Potaro-Siparuni, and the Cuyuni-Mazaruni districts of central Guyana. Species of Xylaria are ascomycetous fungi generally characterized by black, carbonaceous, multiperitheciate ascoma commonly found growing on dead wood. Combined teleomorphic and molecular data indicate that the fungus represents a novel species, described here as Xylaria karyophthora.

The gut of wood-feeding insects is a microhabitat for a specialized community of microbes, including bacteria and several groups of eukaryotes such as nematodes, parabasalids and fungi. The characterization of gut yeast communities from a variety of insects has shown that certain yeasts often are associated with the insects. The gut of wood-feeding insects is rich in ascomycete yeasts and in particular xylose-fermenting (X-F) and assimilating yeasts have been consistently present in the gut of lignicolous insects. The objective of this study was the characterization of the yeast flora from the gut of the wood roach Cryptocercus sp. (Blattodea: Cryptocercidae). Five wood roaches were collected along the Appalachian Trail near the border between Tennessee and North Carolina, USA. We isolated 18 yeast strains from the wood roaches identified as Sugiyamaella paludigena and Sugiyamaella lignohabitans, xylose-assimilating yeasts, and Scheffersomyces cryptocercus (NRRL Y-48824^T = CBS 12658) a new species of X-F yeast. The presence of X-F and certain non X-F yeasts in the gut of the subsocial wood roach Cryptocercus sp. extends the previous findings of associations between certain ascomycete yeasts and lignicolous insects. New combinations were made for 13 asexual members of the Sugiyamaella clade.