solution and approached equilibrium at pH 4.5 (Fig. 2). Several
researches have also investigated the effect of pH on biosorption of
mycotoxin by using different microbial biomass and found similar
results with this study. Ringot et al. (2005) found that optimal
removal of PAT and ochratoxin A by lactic acid bacteria was at pH
5.0. It was explained that the low-pH condition might be responsible
for the resistance of PAT adsorption. Zinedine, Faid, and
Benlemlih (2005) showed that more aflatoxin B1 removal takes
place at pH 5.5 (than pH 3 or pH 4.5). However, Topcu et al. (2010)
noted that the highest removal of PAT by nonviable cells of
Enterococcus strains occurred at pH below 5, this may be due to the
effect of hydrogen bond interactions on removal of PAT. Haskard,
Binnion, and Ahokas (2000) reported that pH in the range from
2.5 to 8.5 did not affected the binding of AFB1 using Lactobacillus
rhamnosus GG, which may indicate that a cation exchange mechanism
was not operating. In general, the effect of pH probably
results from competition for negatively charged binding sites
between toxin and protons (Hþ).