Hydrothermal carbonization aqueous phase (HTC-AP) can be used for methane production by anaerobic digestion (AD). However, it generally had low conversion efficiency due to the formation of complex dissolved organic matters, which depends upon the components of biomass. The present study investigated the characteristics, methane potentials, and recalcitrant chemicals of HTC-AP produced from different combinations of model compounds carbohydrate (α-cellulose, C) and protein (bovine serum albumin, BSA) with mass ratios of 1:0, 0.75:0.25, 0.5:0.5, 0.75:0.25 and 0:1. The methane yields of samples 1:0 (pure C) and 0:1 (pure BSA) were 192 mL/g COD and 187 mL/g COD, respectively, while it was decreased to 105.5 CH₄ mL/g COD for sample 0.75:0.25 (C/BSA), indicating more recalcitrant organics were produced with the combination of C and BSA. It was found that the mean MW (209157) of sample 0.75:0.25 was much higher than the other samples (<7000 Da). While the highest percentage (51 %) of hard bio-degradable hydrophobic DOC, humics, and building blocks organics were also observed in this sample by LC-OCD-OND analysis. Furthermore, a high value of SUVA index 2.56 was noted, indicating the presence of a large number of aromatic compounds. In addition, fluorescent compounds mainly relating to humic-like substances were also detected by 3D-EEM. GC-MS analysis showed higher concentrations of pyrazine and its derivatives were present in sample 0.75:0.25, which indicated the occurrence of a serious Maillard reaction. The continuous experiment further verified the lower biodegradability of sample 0.75:0.25 with a methane yield of 108 mL/g COD. It also showed that only 18.9 % of the fluorescent components were degraded and 13 recalcitrant chemicals were identified to be hard bio-degradable organics in AD process.

水热碳化水相（HTC-AP）可用于通过厌氧消化（AD）生产甲烷。但是，由于形成复杂的溶解有机物而导致转化效率低，这取决于生物质的成分。本研究调查了质量比为1：0、0.75的模型化合物碳水化合物（α-纤维素，C）和蛋白质（牛血清白蛋白，BSA）的不同组合所产生的HTC-AP的特性，甲烷潜能和难降解的化学物质：0.25、0.5：0.5、0.75：0.25和0：1。样品1：0（纯C）和0：1（纯BSA）的甲烷产率分别为192 mL / g COD和187 mL / g COD，同时降低至105.5 CH ₄样品0.75：0.25（C / BSA）的mL / g COD，表明C和BSA的结合产生了更多的顽固有机物。发现样品0.75：0.25的平均MW（209157）比其他样品（<7000 Da）高得多。通过LC-OCD-OND分析，在该样品中还观察到了最高百分比（51％）的可生物降解的硬DOC，腐殖质和结构单元有机物。另外，注意到SUVA指数为2.56的高值，表明存在大量的芳族化合物。另外，还通过3D-EEM检测到主要与类腐殖质有关的荧光化合物。GC-MS分析表明，样品0.75：0.25中存在较高浓度的吡嗪及其衍生物，这表明发生了严重的美拉德反应。连续实验进一步证实了样品0.75：0.25的较低生物降解性，甲烷产率为108 mL / g COD。研究还表明，AD过程中只有18.9％的荧光成分被降解，并且13种难降解的化学物质被确定为难降解的有机物。