Growth inhibition of a phytopathogenic fungus, Colletotrichum species by acetic acid

Abstract

Acetic, oxalic, malic, and citric acids significantly inhibited the growth of Colletotrichurm, gloeosporioides, a phytopathogenic fungus, and acetic acid showed the strongest inhibition with no growth at 50 mM. The growth inhibition by these organic acids was closely related with the inhibition of respiration, as tested using three species, C. gloeosporioides, C. coccodes, and C. dermatium. Optimum growth of C. gloeosporioides was observed around pH 6.0. The inhibition of growth by acetic acid accelerated along with a decrease in pH from 6.0 to 4.0, suggesting that the inhibition might be more enhanced by undissociated form of acetic acid. Despite of growth inhibition by acetic acid, the fungus was able to grow in a normal medium when acetic acid was eliminated, implying that the growth inhibition may be resulted from an acetic acid-mediated inhibition of respiration than a structural damage of cell. Catalase activity of the fungus increased in response to 0.1% hydrogen peroxide, but addition of this together with 30 mM acetic acid brought about a decrease in the activity. The fungus which showed no grow at 30 mM acetic acid or 0.5% hydrogen peroxide began to grow after the elimination of these. But the fungus added simultaneously by these two compounds did not grow at all despite the elimination of these. Thus, controlling of Colletotrichum might be developed using acetic acid which is generally less dangerous than chemical reagents.

Alternative products against anthracnose affect selected primary and secondary metabolites in strawberry fruit

“…This indicates that acetic acid successfully inhibited the infection on strawberry fruit. It has been reported that organic acids and their salts alone on or in combination inhibit the growth of bacteria and fungi [4].…”

“…The optimal growth of Colletotrichum species has been observed at pH 6.0 and the inhibition of growth by acetic acid has been accelerated and linked with a decrease in pH from 6.0 to 4.0 [4]. Several researchers thus propose to control Colletotrichum infection by using acetic acid, which is generally less dangerous than fungicides [4]. Considering the inhibitory role of organic acids, some mechanisms of pathogen repression have been suggested, including membrane disruption with sorbic acid [5] and the interruption of metabolic reactions with benzoate [6].…”

“…Low pH levels require high energy inputs of pathogenic organisms to maintain a favorable intracellular pH. The optimal growth of Colletotrichum species has been observed at pH 6.0 and the inhibition of growth by acetic acid has been accelerated and linked with a decrease in pH from 6.0 to 4.0 [4]. Several researchers thus propose to control Colletotrichum infection by using acetic acid, which is generally less dangerous than fungicides [4].…”

“…Therefore, environmentally friendly control alternatives such as biological control have been sought. The use of antifungal compounds such as bicarbonates [3] and organic acids [4] reportedly reduce the damage caused by C. nymphaeae.…”

Effect of Enzymatic Beech Fagus Sylvatica Wood Hydrolysate on Chlorella Biomass, Fatty Acid and Pigment Production

“…Inhibition of Chlorella growth during heterotrophic cultivation increased with the increase in the neutralized citrate buffer loading from 0.5% to 10%, although further loading increases (15%, 20%) did not alter inhibition rate, which remained as for a 10% loading. Citrate buffer contains citric acid, which has been reported to be inhibitory to bacteria [20] and fungi [21]. Citric acid has also been reported to exert positive [22] or negative [23] effects on Chlorella growth.…”