An endophytic fungus Hypoxylon sp. (BS15) has recently been isolated and found to produce volatile organic compounds (VOCs) that have potential relevance as hydrocarbon fuels. In the work described here, the traditional refined carbohydrate (e.g., sucrose) diet source was replaced by simple sugars produced using a solvent free green chemistry mechanocatalytic method involving ball milling in the solid. BS15 is able to grow on this degraded cellulose as well as the more traditional potato dextrose broth. The volatile compounds produced from both media were largely the same. Unfortunately, it is observed that long term in vitro growth of BS15 results in diminished VOC production. The VOC production was partially restored by cultivating BS15 in growth media containing finely ground woody tissue from the original host plant (Taxodium distichum). Extracts from this woody tissue were made by sequentially extracting with dichloromethane, methanol, and water with a goal of isolating VOC production modulators. Both the dichloromethane and water extracts place on bio-mimicking filter paper were found to modulate VOC production, while the methanol extract had no significant impact. Surprisingly, the woody tissue remaining after exhaustive extraction also acted as a VOC production modulator when combined with the growth media, with noticeable changes in the production of four compounds. This woody tissue also induced production of two compounds not observed in the original BS15 extract, and their changes are inheritable. Remarkably filter paper had the same modulating effect as exhaustively extracted woody tissue, suggesting the modulation was partially due to cellulose degradation products. Extraction of the maximum amounts of VOCs is desirable and here a comparison of solid phase extraction (SPE) and solid phase micro-extraction (SPME) techniques is made. This comparison involves two endophytes, BS15C and Streptomyces ambofaciens (SA 40053). The SPE technique is more effective in retaining compounds having lower vapor pressures and higher boiling points with nearly three to five times more VOC mass obtained versus SPME.
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Doctor of Philosophy (Ph.D.)
College of Sciences
Length of Campus-only Access
Doctoral Dissertation (Campus-only Access)
Wang Kovaleff, Yuemin, "Novel Fuel-producing Fungi and Methodologies for Increasing Fuel Production" (2019). Electronic Theses and Dissertations. 6391.