Growth Stimulation and Inhibition Effects of 4-Hydroxybenzoic Acid and Some Related Compounds on the Freshwater Green Alga Pseudokirchneriella subcapitata

Abstract

4-hydroxybenzoic acid (4-HBA) exhibited low algal toxicity with the 72-h median inhibition concentration (IC50) of 9.9 mmol/L in the standard growth inhibition test using the freshwater green alga Pseudokirchneriella subcapitata. In contrast, it stimulated the algal growth at lower concentrations ranging from 0.1 to 1.0 mmol/L. Comparative studies with benzoic acid and 2- and 3-hydroxybenzoic acids (2-HBA and 3-HBA) indicated that 2-HBA was the most toxic, giving a 72-h IC50 of 0.172 mmol/L, and 4-HBA was the least toxic and that only 4-HBA had the pronounced growth stimulation activity. In a semicontinuous exposure to 4-HBA (0.15 and 0.3 mmol/L), algae maintained increased cell growth compared with controls during up to 10 times consecutive batch cultures, without any indication of adaptive responses to the growth enhancing effect of 4-HBA. Return to the clean standard medium of the exposed cells resulted in the quick recovery from the stimulant effect. Furthermore, 4-HBA (0.3 mmol/L) was found to diminish the toxicity of 2-HBA (<1.0 mmol/L). The presence of such compounds in the complex mixture might interact with other toxicants to alter the whole toxicity when assessed by the algal growth inhibition test. The effects of 4-HBA on P. subcapitata growth observed in the present study are not expected for planktonic algae in the aquatic environments, because known environmental concentrations are far below the effective concentration range.

Biological activities of lignin hydrolysate-related compounds

“…Nevertheless, 4-hydroxybenzoic acid exhibited antimicrobial activities and fungitoxicity, since strongly inhibited the growth of Ganoderma boninense at a concentration of 2.5 mg/ml, which was the highest concentration tested (56). In another report, the algal toxicity of 4-hydroxybenzoic acid was evaluated (57). The toxicity to algae was not very great and actually had the least effect among the various monohydroxybenzoic acids.…”

Probabilistic ecological hazard assessment of parabens using Daphnia magna and Pimephales promelas

“…A metabolite of parabens, p-hydroxybenzoic acid, was used to examine potential growth effects on a freshwater green alga Pseudokirchneriella subcapitata. Algal growth was stimulated at the lower concentrations of 13.8 and 138 mg/L, but growth inhibition was seen at higher concentrations, with a median growth inhibition concentration (IC50) of 1.37 g/L [12]. Eklund [13] observed growth inhibition in four strains of bacteria (Escherichia coli, Pseudomonas American Type Cell Collection [ATCC] 9027, Baccillus subtilis ATCC 6633, and Baccillus subtilis W23) after exposure to methyl-, ethyl-, propyl-, and butylparaben.…”

Effect of Lignocellulose Related Compounds on Microalgae Growth and Product Biosynthesis: A Review

“…In addition to sugar and acetates, other substances such as phenolics and furans are constituents of lignocellulose hydrolysates [98][99][100][101]. Phenolic compounds can be stimulatory or inhibitory for microalgae, but the final effect depends strictly on phenolic structure and concentration, as well as on microalgae strains used [93][94][95]. Furans show inhibitory activity toward microalgae [102,103], but this effect has been scarcely investigated.…”

“…p-Hydroxybenzoic acid had stimulatory effects at lower concentration (up to 138 mg/L) and inhibitory effects at high concentration (1.36 g/L) on the growth of Pseudokirchneriella subcapitata. o-Hydroxybenzoic acid was toxic (13.8-138 mg/L) to Pseudokirchneriella, but the presence of p-hydroxybenzoic acid decreased the negative effect of o-hydroxybenzoic acid [95].…”