Fig. 3
From: Water reuse and growth inhibition mechanisms for cultivation of microalga Euglena gracilis
Identification of growth inhibitors in E. gracilis secretions. a The content of DOM in reused water by using ultrafiltration membrane treatment. b Three-dimensional (3D) fluorescence excitation–emission matrix (FEEM) spectra of DOM (I and II, AP, aromatic proteins; III, FA, fulvic acid-like, IV, SMBM, soluble microbial by product-like material; V, HA, humic acid). c Percent of 6 DOM fractions from reused water of E. gracilis. d UV254 of 6 DOM fractions in 80-fold medium (HoB hydrophobic bases, HiN hydrophilic neutrals, HoA hydrophobic acids, HiB hydrophilic bases, HiA hydrophilic acids, HoN hydrophobic neutrals). e The inhibition rate of growth (IG%) of E. gracilis with stress from different DOM fractions. f The relationship between UV254 and IG% (inset: trendline linear equation and R2 value). Asterisk represents p < 0.05, double asterisk represents p < 0.01. The values represent mean ± SD, where n = 3