Preparation, chemical constituents and antimicrobial activity of pyroligneous acids from salix psammophila branches

In order to improve the additional values of Salix psammophila bio-waste, pyroligneous acids (PAs) from Salix psammophila branches were extracted by the pyrolysis process at two temperature ranges: 90-380°C and 380-550°C. The chemical constituents and antimicrobial activities of PAs were investigated in detail. The GC-MS results showed that 34 compounds were identified from the two kinds of PAs. The main components were organic acids and ketones for PA at 90-380°C, while they were organic acids and phenols for PA at 380-550°C. The total content of acids and phenols was as high as 67.96% for PA at 380-550°C, which contributed to the strong antimicrobial activity. Two PAs both showed good antimicrobial activities for five pathogenic fungi and two pathogenic bacteria, especially against Verticillium dahlia. Compared with the antimicrobial activity of PA at 90-380°C, PA at 380-550°C showed greater antifungal activity but against Fusarium oxysporum.