Component structure and characteristic analysis of cyanobacterial organic matters

Abstract

The characteristic analysis of cyanobacterial organic matters is an important premise of cyanobacterial organic pollution control. This paper investigated the component structure characteristics of algal organic matters (AOM) secreted and released by cyanobacteria in laboratory culture and actual Taihu Lake environment by spectroscopic quantitative and qualitative methods. Results showed that the secretion amount of AOM was mainly 4–6 μg COD/106 cells during the growth period of Microcystis aeruginosa, and the content ratio of extracellular organic matters (EOM) to intracellular organic matters (IOM) gradually increased from 0.83 in adaptation and logarithmic period to 3.33 in stable and decay period. The secretion of IOM showed a decrease trend, which indicated the decrease of its synthesis or the gradual infiltration and loss caused by cell membrane damage. From the component characteristics, the EOM had lower SUVA value and higher proportion of small molecular substances with molecular weight <3 kDa, indicating its more difficult to separate from water than IOM. Compared with the laboratory culture environment, the actual Taihu Lake resulted in more obvious characteristic heterogeneity of cyanobacteria EOM and IOM.

Compositional variations in algal organic matter during distinct growth phases in karst water

“…The changes in SUVA 254 , SUVA 280 , and URI values in different growth stages of the two algae are shown in Figure 2. The SUVA 254 of logarithmic IOM for Chlorella vulgaris and Scenedesmus obliquus was 1.898 ± 0.043 L mg −1 •m −1 and 2.619 ± 0.007 L mg −1 •m −1 (Figure 2A), respectively, suggesting more aromatic substances were produced in IOM during this period (Dong et al, 2019;Sun F. et al, 2022). SUVA 254 in AOM was generally less than 1.5 L mg −1 •m −1 (Zhou et al, 2014), showing that the aromaticity of AOM was low-AOM seemed to contain less protein-like substances and organic nitrogen (Hua et al, 2018).…”