Effects of Pretreatments on Patulin Removal from Apple Juices Using Lactobacilli: Binding Stability in Simulated Gastrointestinal Condition and Modeling

Cypermethrin adsorption by Lactiplantibacillus plantarum and its behavior in a simulated fecal fermentation model

The presence of cypermethrin in the environment and food poses a significant threat to human health. Lactic acid bacteria have shown promise as effective absorbents for xenobiotics and well behaved in wide range of applications. This study aimed to characterize the biosorption behavior of cypermethrin by Lactiplantibacillus plantarum RS60, focusing on cellular components, functional groups, kinetics, and isotherms. Results indicated that RS60 exopolysaccharides played a crucial role removing cypermethrin, with the cell wall and protoplast contributing 71.50% and 30.29% to the overall removal, respectively. Notably, peptidoglycans exhibited a high affinity for cypermethrin binding. The presence of various cellular surface groups including -OH, -NH, -CH3, -CH2, -CH, -P = O, and -CO was responsible for the efficient removal of pollutants. Additionally, the biosorption process demonstrated a good fit with pseudo-second-order and Langmuir-Freundlich isotherm. The biosorption of cypermethrin by L. plantarum RS60 involved complex chemical and physical interactions, as well as intraparticle diffusion and film diffusion. RS60 also effectively reduced cypermethrin residues in a fecal fermentation model, highlighting its potential in mitigating cypermethrin exposure in humans and animals. These findings provided valuable insights into the mechanisms underlying cypermethrin biosorption by lactic acid bacteria and supported the advancement of their application in environmental and health-related contexts. KEY POINTS: • Cypermethrin adsorption by L. plantarum was clarified. • Cell wall and protoplast showed cypermethrin binding ability. • L. plantarum can reduce cypermethrin in a fecal fermentation model.

Induced Expression of the Acinetobacter sp. Oxa Gene in Lactobacillus acidophilus and Its Increased ZEN Degradation Stability by Immobilization

Zearalenone (ZEN, ZEA) contamination in various foods and feeds is a significant global problem. Similar to deoxynivalenol (DON) and other mycotoxins, ZEN in feed mainly enters the body of animals through absorption in the small intestine, resulting in estrogen-like toxicity. In this study, the gene encoding Oxa, a ZEN-degrading enzyme isolated from Acinetobacter SM04, was cloned into Lactobacillus acidophilus ATCC4356, a parthenogenic anaerobic gut probiotic, and the 38 kDa sized Oxa protein was expressed to detoxify ZEN intestinally. The transformed strain L. acidophilus pMG-Oxa acquired the capacity to degrade ZEN, with a degradation rate of 42.95% at 12 h (initial amount: 20 μg/mL). The probiotic properties of L. acidophilus pMG-Oxa (e.g., acid tolerance, bile salt tolerance, and adhesion properties) were not affected by the insertion and intracellular expression of Oxa. Considering the low amount of Oxa expressed by L. acidophilus pMG-Oxa and the damage to enzyme activity by digestive juices, Oxa was immobilized with 3.5% sodium alginate, 3.0% chitosan, and 0.2 M CaCl₂ to improve the ZEN degradation efficiency (from 42.95% to 48.65%) and protect it from digestive juices. The activity of immobilized Oxa was 32-41% higher than that of the free crude enzyme at different temperatures (20-80 °C), pH values (2.0-12.0), storage conditions (4 °C and 25 °C), and gastrointestinal simulated digestion conditions. Accordingly, immobilized Oxa could be resistant to adverse environmental conditions. Owing to the colonization, efficient degradation performance, and probiotic functionality of L. acidophilus, it is an ideal host for detoxifying residual ZEN in vivo, demonstrating great potential for application in the feed industry.

The Effect of Bovine Serum Albumin on Benzo[a]pyrene Removal by Lactobacillus Strains

The aim of this study was to investigate the influence of bovine serum albumin (BSA) on the Lactobacillus-strain-mediated removal of benzo[a]pyrene (BaP). A combination of 0.5 mg/mL of BSA with 1.0 × 10¹⁰ CFU/mL bacterial cells had a removal of 49.61% BaP for strain 121, while a combination of 0.4 mg/mL of BSA with 1.0 × 10¹⁰ CFU/mL bacterial cells had a removal of 66.09% BaP for strain ML32. The results indicated that the binding of BaP to Lactobacillus-BSA was stable. BSA maintains Lactobacillus activity and BaP removal in the gastrointestinal environment. Heat and ultrasonic treatment of BSA reduced the BaP-binding ability of Lactobacillus-BSA. With the addition of BSA, the surface properties of the two strains affected BaP binding. The Fourier-transform infrared (FTIR) data demonstrated that O-H, N-H, C=O, and P=O groups were involved in the binding of BaP to Lactobacillus-BSA. Scanning electron microscopy (SEM) results revealed that the morphology of Lactobacillus-BSA bound to BaP was maintained. The adsorption of BaP by Lactobacillus-BSA was appropriately described by the pseudo-second-order kinetic model and Freundlich isotherm model. BSA enhances the affinity between the bacterial cells and BaP.

Impact of simulated microgravity on bioremoval of heavy-metals by Lactobacillus acidophilus ATCC 4356 from water

There are several reports about the effect of gravity removal on some characteristics of microorganisms due to possible change in surface layer thickness and adherence properties. In this study, bioremoval efficiency of Lactobacillus acidophilus ATCC 4356 from water under simulated microgravity conditions was investigated. Furthermore, pretreatment effects (untreated, NaOH, and heat pretreated) of L. acidophilus ATCC 4356 on heavy metal removal was evaluated on microgravity, as our previous research showed impact of pretreatment on adherence properties of probiotics to environmental metals. The results showed that ability of L. acidophilus for arsenic adsorption enhanced following heat-pretreatment in simulated and normal gravity. Moreover, in both conditions of simulated microgravity and normal gravity NaOH-treated L. acidophilus increased the removal of cadmium and lead. In none of the conditions, pretreatment of lactobacillus affects mercury removal. Evaluation of stability of binding of L. acidophilus-heavy metal was investigated to check irreversibility of complex formation between microorganisms and metals in simulated gastrointestinal conditions. Data showed release of heavy metals from complex in normal gravity. Obtained results of this research show the favorable potential of simulated microgravity condition to increase bioremoval capacity of L. acidophilus for heavy metals.

Adsorption Behavior of 3-phenoxybenzoic Acid by Lactobacillus Plantarum and Its Potential Application in Simulated Digestive Juices

3-PBA is a major degradation intermediate of pyrethroids. Its widespread existence in the environment poses a severe threat to the ecosystem and human health. This study evaluated the adsorption capacity of L. plantarum RS20 toward 3-PBA. Batch adsorption experiments indicated that the optimal adsorption conditions were a temperature of 37 °C and initial pH of 6.0–8.0, under which the removal rate was positively correlated with the cell concentration. In addition, there was no link between the incubation time and adsorption rate. The kinetic study showed that the adsorption process fitted well with the pseudo-second-order model, and the adsorption isotherms could be described by both Langmuir and Freundlich equations. Heat and acid treatments showed that the ability of strain RS20 in removing 3-PBA was independent of microbial vitality. Indeed, it was involved with chemisorption and physisorption via the cell walls. The cell walls made the highest contribution to 3-PBA removal, according to the adsorption experiments using different cellular components. This finding was further reconfirmed by SEM. FTIR spectroscopy analysis indicated that carboxyl, hydroxyl, amino groups, and –C–N were the functional sites for the binding of 3-PBA. The co-culture experiments showed that the adsorption of strain RS20 enhanced the degradation of 3-PBA by strain SC-1. Strain RS20 could also survive and effectively remove 3-PBA in simulated digestive juices. Collectively, strain RS20 could be employed as a biological detoxification agent for humans and animals by eliminating 3-PBA from foods, feeds, and the digestive tract in the future.

Role of the lactobacilli in food bio-decontamination: Friends with benefits

Food contamination such as toxins and heavy metals has been increasing in the last few decades as a result of industrialization in general and as part of food production in particular. Application of microorganisms in toxins and heavy metals bio-removal has been documented and applied as a favorable decontamination approach due to being environmentally friendly, reasonably simple, and economically feasible. Lactobacilli have been proposed and applied as a beneficial biologic sorbent for toxins and heavy metals in processes of reducing their hazardous bio-availability. The purpose of this review is to summarize the known role of Lactobacillus bacterial species in food bio-decontamination processes. After a quick glimpse of the worthy properties of lactobacilli, their cell wall structure is mentioned. Then the potential role of Lactobacillus strains for mycotoxins (aflatoxins, patulin, ochratoxin A, fumonisins, zearalenone, cyanotoxins, and trichothecenes) and heavy metals (lead, arsenic copper, mercury, cadmium, zinc, aluminum, chromium, and iron) bio-removal were described. In addition, the role of various factors in removal yield and the decontamination mechanism were explained. Finally, the lactobacilli-contaminant stability, in vivo studies, and being a friend or foe of Lactobacillus bacteria are discussed.

The synergy of mercury biosorption through Brevundimonas sp. IITISM22: Kinetics, isotherm, and thermodynamic modeling

This research experiment was conducted to investigate the potential of Brevundimonas species IITISM22 to remove mercury by using live biomass of bacterial cells at 298, 308, and 318 K. Characterization of bio-sorbent was done by FT-IR and SEM-EDX. The prime functional groups accountable for binding Hg were OH, -NH₂, -CH, -SH and -COO. The deformed bacterial structure was seen after Hg adsorption over the bacterial cell. Influences of different experimental factors, such as pH, temperature, contact time, Hg concentration, and biomass dose was examined. IITISM22 exhibited the highest Hg absorption at pH 6.5, contact time of 4 h, and showed an increased adsorption capacity while increasing the concentration of Hg. Kinetics were recommended by pseudo-second-order for adsorption process and isotherm was adequately defined by the Linear Langmuir isotherm model (K_L) = 1.4, 1.2, 0.9 mg/l; (R_L) = 0.020, 0.015, 0.013, respectively than Freundlich isotherm model. The Activation energy (E_a) of biosorption calculated were (131.10 KJ/mole) by using Arrhenius equation, and the thermodynamic parameters were ΔG⸰ (-41.03, -16.33, -16.12 KJ/mol), ΔH⸰ (-36.87 KJ/mol) and ΔS⸰ (-194.03 J/mol), respectively. These findings suggest that the removal process was based on chemisorption and the biosorption was exothermic. The result of the current experiment indicated that the IITISM22 could be an authentic biosorbent for Hg detoxification.