Adsorption of Lactobacillus acidophilus on attapulgite: Kinetics and thermodynamics and survival in simulated gastrointestinal conditions

•Lactobacillus acidophilus was successfully adsorbed on attapulgite.•The kinetics and thermodynamics of adsorbed bacteria were investigated.•The adsorption was a spontaneous and endothermic process.•The adsorption could efficiently improved survivals of L. acidophilus cells.

In the present study, we investigated the optimum adsorption conditions, adsorption characteristics and surviva of Lactobacillus acidophilus adsorbed on attapulgite (ATT). Results of single factor experiments showed that the optimum adsorption parameters were ATT concentration of 10%, initial pH of 6.5 and temperature of 35 °C. From the static experiments of adsorption characteristics, we found that the experimental data were fitted best to the pseudo-secondorder kinetics and Langmuir isotherm models, and the adsorption was a spontaneous and endothermic process. Bacteria survival test showed that the microencapsulated L. acidophilus stored at −18 °C for 30 days achieved the highest survival rate (83.2% ± 5.8) and obtained better protection at simulated conditions of gastric pH and at high bile salt concentrations when compared with free bacteria. The study demonstrated that microencapsulation of L. acidophilus in ATT was an effective technique of protection against low-temperature injury and under simulated gastrointestinal environment.