Ash in LY294002 antibiotic mycelial residue would partially dissolve into water in HTT and be leached out in centrifugation. The mass of ash remaining in the HTT produced solid biofuels was calculated as the ash content of the fuels in Table 2 and the total mass of the biofuels. Its mass in 200 g raw antibiotic mycelial dreg without centrifugation was used to determine the original ash content in the antibiotic mycelial dreg. Fig. 7 shows the percents of ash in the HTT produced solid biofuels from different temperatures, where the pink bar indicates the ash lost during fuel preparation process, which includes dissolution in HTT and leaching via centrifugation. About 17% ash in raw antibiotic mycelial dreg was lost via leaching in centrifugation (denoted as “No HTT” in Fig. 7). Comparing to antibiotic mycelial dreg (100% ash), the ash loss for the 160 °C HTT produced solid biofuel was the highest which reached 55%. Increasing the HTT temperature decreased the ash loss. For example, ash decreased to 40% for the HTT at 220 °C. The results means that at higher HTT temperatures more ash components tended to precipitate and retain in the solid biofuels, whereas at lower HTT temperatures there were more ash species dissolving into the liquid phase and in turn leached out by centrifugation after HTT.