Volatile organic compound production by organisms in the genus Ascocoryne and a re-evaluation of myco-diesel production by NRRL 50072

Abstract

The Patagonian fungal endophyte NRRL 50072 is reported to produce a variety of mediumchain and highly branched volatile organic compounds (VOCs) that have been highlighted for their potential as fuel alternatives and are collectively termed myco-diesel. To assess the novelty of this observation, we determined the extent to which ten closely related Ascocoryne strains from commercial culture collections possess similar VOC production capability. DNA sequencing established a high genetic similarity between NRRL 50072 and each Ascocoryne isolate, consistent with its reassignment as Ascocoryne sarcoides. The Ascocoryne strains did not produce highly branched medium-chain-length alkanes, and efforts to reproduce the branched alkane production of NRRL 50072 were unsuccessful. However, we confirmed the production of 30 other products and expanded the list of VOCs for NRRL 50072 and members of the genus Ascocoryne. VOCs detected from the cultures consisted of short-and mediumchain alkenes, ketones, esters and alcohols and several sesquiterpenes. Ascocoryne strains NRRL 50072 and CBS 309.71 produced a more diverse range of volatiles than the other isolates tested. CBS 309.71 also showed enhanced production compared with other strains when grown on cellulose agar. Collectively, the members of the genus Ascocoryne demonstrated production of over 100 individual compounds, with a third of the short-and medium-chain compounds also produced when cultures were grown on a cellulose substrate. This comparative production analysis could facilitate future studies to identify and manipulate the biosynthetic machinery responsible for production of individual VOCs, including several that have a potential application as biofuels.

Identification of a Fungal 1,8-Cineole Synthase from Hypoxylon sp. with Specificity Determinants in Common with the Plant Synthases

“…Isolates observed growing from the stems were transferred to a new 1ϫ PDA plate. For VOC analysis, agar plugs were inoculated into sealed vials with both 1ϫ PDA and potato dextrose broth, as described previously (37). Vials were sampled after growth at 23°C for 4, 8, and 12 days.…”

“…They have been explored for the production of VOCs, and many of them produce an abundance of terpenes (37). Recently, three endophytic fungi in the family Xylariaceae, identified as Hypoxylon sp.…”

Volatile sesquiterpenes from fungi: what are they good for?

“…The ascomycete Ascocoryne sarcoides is an endophyte from Patagonia and produces a variety of volatile organic compounds that have been suggested as fuel alternatives, termed myco-diesel. Several of these strains produced considerable amounts of sesquiterpenes as well and one strain produced no less than 49 different sesquiterpenes, however, none of them has been identified (Griffin et al 2010). …”

Evaluation of Cellulose as a Substrate for Hydrocarbon Fuel Production by <i>Ascocoryne sarcoides</i> (NRRL 50072)

“…Ascocoryne sarcoides (NRRL 50072) is a cellulolytic fungal endophyte capable of direct conversion of cellulosic materials to fuel-related hydrocarbon compounds such as alkanes, alcohols and aromatics [5] [6]. A. sarcoides was one of the first discovered endophytic fungi with fuel-related compound production in the C 5 -C 10 carbon chain length range.…”