Identification of cultured bacteria separated from an excavated waterlogged wood and lacquer

Abstract:

[Background] According to relevant researches, waterlogged archaeological wood is vulnerable to degradation by microorganisms. Concerning the microbial damage of waterlogged archaeological wood, many studies have been carried out overseas, but few reported in China. [Objective] This study is aimed at analyzing the bacteria population in waterlogged archaeological wood and their degradation on wood when preserved in water. [Methods] Bacteria were identified by physiological and biochemical test and 16S rRNA gene sequence analysis. Typical bacteria strains were inoculated into wood that were used to test the wood degradation. The number of bacteria used to inoculate was 5×108 and the inoculated wood was cultured at 37 °C for 120 d. [Results] In total 53 strains were separated from F446 and the water sample. The dominant genus of these strains with number of 21, was Bacillus. Eleven of them belong to the genus of Brevibacterium, four are Brevundimonas, five are Alcaligenes faecalis, five are Altererythrobacter, two are Flavobacterium mizutaii, one is Pseudochrobactrum saccharolyticum, Lysinibacillus fusiformis, one Leucobacter aridicollis, one Paenibacillus, and one Ochrobactrum pseudogrignonense. Furthermore, strains A5 and A6 are likely new species of Paenibacillus and Altererythrobacter. Fifteen typical strains were selected to test the corrosion. Nine strains have extremely significant difference compared to the control. Some bacteria corroded wood but the corrosion rate was lower. It indicated that these bacteria could not cause severe corrosion to the wood of Pinus massoniana. [Conclusion] During a short period, bacterial driven wood-corrosion was not obvious when the archaeological waterlogged wood was preserved in water after excavated.