Application Of Citric Acid Research Articles

Citric acid: fermentative production using organic wastes as feedstocks

Abstract Citric acid is the most important organic acid produced in tonnage and is used extensively in the pharmaceutical, chemical and food industries due to its low cost and high efficiency compared to other acidulates. Citric acid is produced by fungi, bacteria and yeasts under solid-state and submerged state fermentations. Aspergillus niger is one of the most dominant producer of citric acid. Different fruit wastes and agricultural residues are employed as surplus resources for microbial production of citric acid. In this review, the microbial sources and different organic wastes involved in citric acid production have been discussed. Furthermore, the recovery, purification and application of citric acid in different human utilities have also been reviewed.

Physiological mechanisms of exogenous organic acids to alleviate aluminum toxicity in seedlings of mungbean, buckwheat, and rice

One of the major constraints for crop yield in acidic soils is the phytotoxicity of aluminum ions (Al3+), which primarily affects the roots. To mitigate the harmful effects of Al toxicity, plants use organic acids to chelate Al internally and externally. In this study, the effects of exogenous organic acids on Al toxicity in rice, mung bean, and buckwheat were investigated. Specifically, the study examined the ameliorative effect of three organic acids (oxalic acid, malic acid, and citric acid, each at a concentration of (100 μmol/L) on root elongation, fresh weight, Al content, organic acid key enzymes, and rhizosphere pH in hydroponic media containing (100 μmol/L) Al. The experimental results revealed species-specific responses to aluminum tolerance and the alleviating effects of different organic acids. Buckwheat was found to be the most aluminum-tolerant, followed by mung bean, while rice was the least tolerant. Exogenous application of oxalic acid promoted root elongation, increased root fresh weight, and enhanced the activity of the PEPC enzyme in mung bean. Malic acid, on the other hand, alleviated Al toxicity in rice by promoting root elongation, increasing root fresh weight, enhancing the activity of the PEPC enzyme, and decreasing the activity of the MDH enzyme. In buckwheat, citric acid application reduced Al toxicity by promoting root elongation, increasing root weight, and decreasing the activities of CS and GO enzymes. These findings indicate that different organic acids can reduce Al toxicity in different plant species by employing different physiological mechanisms.

Effect of Citric Acid on the Properties of Sapwood of Pinus sylvestris Submitted to Thermomechanical Treatment

The present study aimed to evaluate the effect of citric acid on the properties of solid pine wood, which were submitted to thermomechanical treatment. A preliminary test was performed in a previous study to evaluate the influence of different temperatures of pressing and concentrations of citric acid on the physical properties of wood. After choosing the best treatments (170 °C and 5% and 10% of citric acid), the effect of these on the chemical properties (SEM, FTIR and pH); on the density profile using an X-ray microtomography and on the resistance to aging through an abrasion test were evaluated. The result of the chemical analysis showed an increase of the presence of ester functional groups, as well as better coverage and higher acidity of the surface. The density profile technique allowed us to observe the formation of peaks of density on the surface where the acid was applied. Lastly, it was also possible to verify an increase in the resistance to abrasions because of the application of citric acid.

Effect of citric acid on phytoextraction potential of Cucurbita pepo, Lagenaria siceraria, and Raphanus sativus plants exposed to multi-metal stress

Phytoextraction is a novel technique that involves using plants to remove heavy metals from contaminated soils. An outdoor pot experiment was designed to evaluate the phytoextraction potential of three plant species Cucurbita pepo, Lagenaria siceraria, and Raphanus sativus in soil contaminated with multiple metals (Cd, Co, Cr, Cu, Ni, Pb, and Zn) under the application of citric acid. The results showed that Raphanus sativus, out of all the studied plants, had the highest root and shoot dry weight and the capacity to accumulate all heavy metals at higher concentrations except for Cu. The application of citric acid into the polluted soil significantly increased plant growth, biomass, and heavy metal uptake. High bioconcentration values indicate that Raphanus sativus is a promising plant for absorbing and accumulating Cd and Ni from the soil. The maximum values of bioconcentration were also observed by the application of citric acid. The values of metal translocation from the root to the shoot were varied by plant species and the citric acid application. Regarding the biomass, metal content, as well as removal metal percentage values, it became apparent that the Raphanus sativus plant was the most effective crop in removing heavy metals from multi-metal contaminated Soil. Generally, these findings emphasize that the application of citric acid could be a useful approach to assist Cd and Ni phytoextraction by Raphanus sativus plants. When these plants are growing as vegetable crops, more attention should be given to evaluating the heavy metal content in them, especially when adding citric acid to their soil through fertigation systems to avoid food chain contamination.

Effect of CaCl2 and Citric acid on Physio-chemical Changes and Storage at Ambient Temperature of Cherry (Prunus avium) Candy

Candy processing is essential to create a wide variety of delicious and appealing treats, ensuring quality control, flavor consistency, and efficient production for consumer enjoyment. The present experiment was carried out during 2022-23 in Post Harvest Laboratory of Department of Horticulture, SHUATS, Prayagraj. The experiment was conducted in Completely Randomized Design with 8 treatment replicated thrice. The treatments were T0 (Control), T1 (Application of CaCl2 @1% +70 ºBrix sugar), T2(Application of CaCl2 @1.5% + 70 ºBrix sugar), T3 (Application of CaCl2 @ 2%+ 70 ºBrix sugar), T4 (Application of Erythrosine @0.05%+ 70 ºBrix sugar), T5 (Application of Citric Acid @ 1%+ 70 ºBrix sugar), T6 (Application of Citric Acid @ 1.5%+ 70 ºBrix sugar), T7 (Application of Citric Acid @ 2% + 70 ºBrix sugar). On the basis of our experimental finding it was found that the treatment T2 (Application of CaCl2 @1.5 mg/100 g + 70 ºBrix sugar) was found to be best in the terms of TSS, Total sugar, Reducing sugar, Moisture content, Ascorbic acid, pH, Acidity %, Taste, Color and appearance, aroma, texture, overall acceptability and benefit cost ratio.

Effects of Citric Acid and Humic-like Substances on Yield, Enzyme Activities, and Expression of Genes Involved in Iron Uptake in Tomato Plants

Iron (Fe) deficiency is a common abiotic stress on plants growing in calcareous soils where low organic matter content, high carbonate–bicarbonate concentration, and high pH precipitate Fe in unavailable forms. Enzymatic activity is a mechanism for plants to access soil nutrients; enzymes such as H+-ATPase, phosphoenolpyruvate carboxylase (PEPC), and the intracellular enzyme ferric reduction oxidase (FRO) are involved in Fe absorption. The effects of the application of citric acid (CA) and humic-like substances (HLS) on the yield, H+-ATPase, PEPC, and FRO enzyme activity, and expression of LeHA1, LePEPC1, and LeFRO1 genes in tomato plants grown under calcareous soil were studied. CA and HLS improved the SPAD units and increased the number of harvested fruits and yield per plant. Temporary alterations in enzyme activity, which reduced PEPC and FRO activity in roots, were documented. In leaf tissue, CA resulted in lower expression of LeHA1 and LePEPC1 and the induction of LeFRO1 expression, whereas HLS application resulted in higher expression of LePEPC1 and LeFRO1. In roots, LeHA1 expression increased with HLS, whereas LePEPC1 and LeFRO1 showed lower expression with CA and HLS, respectively. The application of CA and HLS through a nutrient solution in combination with Fe-chelate can improve Fe nutrition in tomato plants potted in calcareous soil by inducing temporal alterations in PEPC and FRO enzyme activity and LeFRO1 and LeHA1 gene expression.

Application of Chitosan and Citric Acid Coating to Increase The Storage of Marigold Flowers (Tagetes Patula L.)

Marigold is a flower that can be consumed (edible flower) in fresh condition. Marigold flower damage is characterized by withering and changing the color of the petals to brown (browning). Coating treatment combined with citric acid is expected to be one of the solutions to maintain quality and increase the shelf life of Marigold flowers.. This study aims to examine the effect of citric acid treatment and application of coating made from chitosan on changes in the quality of Marigold flowers as fresh edible flowers. The concentrations of chitosan (K) studied were 0.05% and 0.1%; while the concentration of citric acid (A) was 1% and 2%. Citric acid solution is sprayed first. After air dried, the flowers were sprayed with a coating solution and air-dried. All flower samples, both control and treatment, were packaged and stored at 10oC. During storage, respiration rate, moisture content, weight loss and color were measured. Organoleptic test was carried out by 35 panelists with hedonic values 0-5. The best treatment was A2K2 (2% citric acid and 0.1% chitosan) which was still accepted by the panelists (score 3) until the 6th day of storage with a moisture content of 83.04%, weight loss 21.05%, and the value of °hue 79.70°. A2K2 treatment could increase the shelf life of three days longer than the control. Keywords: Chitosan, Citric acid, Coating, Edible flower, Marigold flower.

Bio-hyperbranched polyesters synthesized from citric acid and bio-polyols and applications on wood adhesives

Biomass-based adhesives have attracted extensive research interest in recent years as an effective alternative to formaldehyde-based adhesives which are non-renewable and harmful to human health. In this paper, citric acid-based hyperbranched polyester (HBPCA) resins were synthesized by green and simple strategy using natural citric acid (CA) and succinic anhydride (SA) as raw materials. Hyperbranched polyol (HBP) was prepared by nucleophilic addition reaction of SA with diethanolamine and later condensed with CA to produce HBPCA resins. The chemical structure of HBPCA resins was characterized using Fourier transform infrared spectroscopy (FTIR), 13C nuclear magnetic resonance (13C NMR), X-ray photoelectron spectroscopy (XPS), liquid chromatography−mass spectrometry (LC-MS), and gel permeation chromatography (GPC). The introduction of HBP enabled the resins to form a hyperbranched network cross-linked structure, which increased the cross-link density and thus prevented the intrusion of moisture. The results showed that HBPCA resin plywood has excellent adhesive strength and water resistance. The shear strength was 1.49 MPa and 1.47 MPa after immersion in hot water at 63 °C and boiling water at 93 °C for 3 h. The green and simple synthesis of HBPCA resins and their excellent properties provide a novel strategy for preparing biomass-based adhesives.

Accumulation Potential Cadmium and Lead by Sunflower (Helianthus annuus L.) under Citric and Glutaric Acid-Assisted Phytoextraction.

Organic acid assistance is one of the effective methods for phytoremediation of heavy metal contaminated soil. In this experiment, the addition of citric and glutaric acids was selected to improve the accumulation of cadmium and lead by Helianthus annuus L. Results showed that citric and glutaric acids elevated the growth of the plants and stimulated Cd/Pb uptake by plant in single Cd/Pb treatments, but glutaric acid showed inhibitory action on the uptake of metals in complex treatments. Organic acids impacted the translocation of Cd/Pb differently, and citric acids (30 mg·L-1) enhanced the translocation of Cd to aerial parts of the plants in Cd (5 mg·kg-1) and Cd (10 mg·kg-1) plus Pb treatments. Glutaric acid (30 mg·L-1) could promote the translocation factors in the complex treatments of Cd (5 mg·kg-1) with Pb (50, 100 mg·kg-1) added. The application of citric and glutaric acid could be conducive to increase floral growth when proper doses are used, and incorporation of these organic acids can be a useful approach to assist cadmium and lead uptake by sunflower. However, growth, bioaccumulation, and translocation of metals may differ due to the metals' property, kinds, and concentrations of organic acids.

An application of citric acid as a carrier for solid dispersion to improve the dissolution and uric acid-lowering effect of kaempferol

Abstract Kaempferol (KPF) is a flavonoid compound, which has a variety of pharmacological activities, and widely exists in daily diet. However, its application is limited due to poor solubility. Citric acid (CA) is a common food additive with high solubility. In this study, solid dispersion (SD) was prepared with CA as the carrier to improve the solubility of KPF. KPF-CA-SD (weight ratio 1:20) was obtained by ultrasonic for 20 min at 40 °C. The in vitro dissolution of KPF in SD was increased from about 50% to more than 80%. The physicochemical characterizations were analyzed by X-ray diffraction, differential scanning calorimetry, Fourier transform infrared spectroscopy, and scanning electron microscope. In hyperuricemia mice, KPF-SD (equivalent to 100 mg/kg KPF) can effectively reduce serum uric acid and exert nephroprotective effects. In conclusion, the preparation of SD with CA might provide a safe and effective selection to facilitate application of KPF in food and medicine.

Effects of single and combined applications of three root exudates of Sedum plumbizincicola on the phytoremediation efficiency of paddy soil contaminated with Cd

Root exudates are carriers for the transfer of material, energy and information between plant roots and soils. Plants encountering environmental stresses such as heavy metal pollution adapt to the environment by producing and secreting root exudates. In this study, laboratory soil culture experiment and pot experiment with Sedum plumbizincicola were used to study the effects of single and combined application of three root exudates, citric acid, glycine, and fructose, on the Cd-activation and phytoremediation of Cd-contaminated paddy soil. Results from the soil culture experiment showed that for the single application of root exudates, all three root exudates significantly activated the Cd in soil as presented by the increased content of diethylenetriamine pentaacetic acid extracted Cd (DTPA-Cd). In Particular, citric acid (SC) at a relatively low concentration (2 mmol/kg) exhibited the best Cd activation efficiency by increasing DTPA-Cd in the soil by 66.12%. For the combined application of root exudates, citric acid in combination with glycine (SC + G, 1:3) had the best activation effect on the Cd in the soil. In the phytoremediation pot experiment, both the single application of citric acid at a low concentrate (1 mmol/kg) and the combined application of citric acid and glycine (1:1) significantly reduced the total Cd and DTPA-Cd in the soil and increased the biomass and the content of Cd in S. plumbizincicola; thus, the phytoremediation efficiency of Cd-contaminated soil increased by 42.33% and 35.61%. The results from this study suggest that citric acid plays a crucial role in Cd activation and phytoremediation with single or combined applications with glycine. However, the mechanisms under the synergetic interaction between citric acid and glycine require further investigation.

Seed priming and exogenous application of citric acid enhance seedling growth and photosynthetic pigments and mitigate oxidative damage of soybean (Glycine max) under salt stress

Seed priming and citric acid (CA) supplementation on germination and seedling growth of soybeans were investigated. Soybean seeds were primed with distilled water (control), 1 mM CA (CA1), or 2 mM CA (CA2) and then placed for germination in Petri dishes containing distilled water or 150 mM NaCl (SS), alone or in combination with 1 mM or 2 mM CA. Germinated seeds were placed in hydroponic pots using a similar treatment regimen to that specified for the Petri dishes to obtain seedling growth and biochemical parameters. Salt stress significantly lowered germination, growth traits, relative water content (RWC), and photosynthetic pigment. When soybean seeds were primed with CA under salt stress, the germination rate, final germination percentage, seed vigor index, and number of lateral roots significantly increased. Moreover, supplementation of CA significantly increased fresh and dry shoot and root weight, plant height, RWC, and photosynthetic pigments compared to salt-treated plants. The results also displayed that salt stress considerably increased hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents compared to control plants. Spraying of CA1 and CA2 significantly lowered the levels of H2O2 and MDA in salt-treated plants. Both hierarchical clustering and PCA revealed that the effects of salt stress and CA on germination, growth characteristics, photosynthetic pigments, H2O2, and MDA concentrations strongly interacted with one another. According to the findings, CA could be applied as a seed priming and exogenous agent to help soybeans grow more quickly when exposed to salt stress.

Citric Acid Induces the Increase in Lenthionine Content in Shiitake Mushroom, Lentinula edodes.

Shiitake mushroom, Lentinula edodes, is the second largest edible fungus in the world, with a characteristic aroma. 1,2,3,5,6-pentathioheterocycloheptane, commonly known as lenthionine, is the main source of this aroma. Lenthionine has high commercial value, and if we explore the possible induction mechanism of citric acid in lenthionine synthesis, we can provide a reference for the effective application of citric acid as an inducer. In this paper, the single-factor treatment of Lentinula edodes with variable citric acid concentration and treatment duration showed that the best citric acid concentration for L. edodes was 300 μM, and the best treatment duration was 15 days. Additionally, the optimal design conditions were obtained using the response surface method (RSM); the treatment concentration was 406 μM/L, the treatment duration was 15.6 days, and the lenthionine content was 130 μg/g. γ-Glutamyl transpeptidase (LEGGT) and cystine sulfoxide lyase (LECSL) are the key enzymes involved in the biosynthesis of lanthionine. The expression levels of LEGGT and LECSL genes increased significantly under citric acid treatment. Additionally, the lenthionine content of the silenced strains of LEGGT and LECSL was significantly decreased.

Exogenous application of citric acid alleviates copper-induced stress in Withania coagulans (Dunal)

The current study aimed to determine the mitigating effect of citric acid (CA) on various physiological and biochemical attributes in Withania coagulans, exposed to copper (Cu) stress. The viable seeds of Withania coagulans were planted in a controlled environment. After reaching the four-leaf stage, the plants were given simultaneous treatment with two concentrations of Cu [TCu1 and TCu2 (10mM, 15mM)] alone and/or with CA [TCa1 and TCa2 (05mM, 10mM)]. After harvesting, the physiological and biochemical characteristics of the plants were assessed. The findings demonstrated that using a higher dosage of Cu has significant toxic effects on plant growth and biomass. The agronomic attributes of the plant were significantly reduced by 24% (number of leaves), 22% (shoot length), 7% (root length), 8% (fresh weight), and 38% (dry weight) compared to the control. Higher concentration of Cu was also found toxic to photosynthetic pigments and significantly reduced by 27% (chl a), 6% (chl b), and 35% (carotenoids) compared to the control. However, the application of CA under Cu stress significantly improved the physiological attributes of Withania coagulans. The plant's agronomic traits significantly increased by 66% (number of leaves), 31% (shoot length), 87% (root length), 43% (fresh weight), and 78% (dry weight), whereas photosynthetic pigments by 25% (chl a), 58% (chl b), and 125% (carotenoids). Based on the results, it could be concluded that CA can play a role in mitigating the toxic effect of Cu in Withania coagulans

Examining the Effect of Organic Acids on Inactivation of Hepatitis E Virus

Infection with hepatitis E virus genotype 3 (HEV-3) is an emerging cause of illness in developed countries. In North America and Europe, HEV-3 has been increasingly detected in swine, and exposure to pigs and pork products is considered the primary source of infection. We have previously demonstrated the prevalence of the HEV-3 genome in commercial pork products in Canada. In this study, we investigated the application of citric acid and acetic acid to inactivate HEV-3 on food and on food contact surfaces. For this purpose, plastic, stainless steel, and pork pâté surfaces were inoculated with HEV-3 and were treated with acetic acid or citric acid at 1, 3, or 5%. The infectivity of posttreatment viral particles was determined by cell culture. A greater than 2-log reduction in viral infectivity was observed on plastic and stainless steel treated with the organic acids, but the treatment was less effective on HEV infectivity on pork pâté (average reductions of 0.47 log citric acid and 0.63 log acetic acid). Therefore, we conclude that citric acid and acetic acid have potential application to control HEV-3 on food contact surfaces but are not suitable for food.

Insights into Cadmium-Induced Morphophysiological Disorders in Althea rosea Cavan and Its Phytoremediation through the Exogeneous Citric Acid

Cadmium (Cd) is taken in plants from soil and then travels through the food cycle, posing a major threat to all the units of the ecosystem. A pot experiment was conducted to understand the influence of citric acid (CA) on Cadmium (Cd) phytoextraction ability of hollyhock (Althea rosea Cavan.). A. rosea plants were exposed to Cd concentrations (100 and 200 mg·kg−1), either in simultaneous administration or without adding CA (5 mM·kg−1 dry weight). The results revealed that exposing A. rosea to different levels of Cd stress, i.e., 100 and 200 mg·kg−1, significantly decreased (p < 0.05) plant growth and biochemical attributes, such as root length (RL), shoot length (SL), fresh biomass (FW), dry biomass (DW), relative water content (RWC), and chlorophyll and carotenoid contents. Meanwhile, a net increase in MDA and REL indicated Cd-induced oxidative stress in plants. However, the application of citric acid (CA) as an organic chelator helped the plants to alleviate the phytotoxic effects of Cd stress on A. rosea, which is shown in terms of enhancing plant growth and biomass; that is, the root length (27.3% and 21.12%), shoot length (32.11% and 23.02%), fresh weight (39.66% and 29.8%), and dry weight (29.8% and 57.33%) under 100 and 200 mg·kg−1 of Cd stress, respectively, were observed. CA application also helped to alleviate the level of chlorophyll and carotenoid contents; foster high level of antioxidants, such as SOD, POD, CAT, and APX; and lower concentration of MDA and EL. In addition to enhancing plant-growth attributes, the application of CA also managed to increase the phytoextraction potential of the plants by enhancing the concentration of Cd in roots and shoots tissues. This is also demonstrated by rising levels of bioaccumulation (BAC) and translocation factors (TFs). These findings showed that CA application could be a practical strategy to apply to ornamental plants, such as A. rosea seedlings, cultivated in Cd-contaminated locations, opening ways to cope with Cd stress and enhanced phytoextraction.

ISOLATION AND SCREENING FOR CITRIC ACID PRODUCTION BY ASPERGILLUS NIGER USING SUCROSE AS A CARBON SOURCE

The numerous applications of citric acid have increased its demand. It is of great importance toproduce citric acid using adequate monosaccharides and dissacharides as they have proven to beeasily catabolyzed and decomposed by Fungi when compared to polysaccharides. The superiorityof sucrose to other sugars is a result of strong extracellular mycelium-bound invertase of A. nigerwhich rapidly hydrolyses sucrose at low pH. This project was undertaken to isolate, screen andproduce citric acid in a submerged fermentation by four different strains of Aspergillus niger usingsucrose. Aspergillus niger was isolated and characterized from garden soil. Citric acid productionfrom Aspergillus niger in a submerged basal medium was quantitatively determined usingtitrimetric method. Aspergillus niger strain HUS1 (ASHUS1), Aspergillus niger strain HUS7(ASHUS7), Aspergillus niger strain HG49 (ASHG49) and Aspergillus niger strain AN8 (ASAN8)showed significant accumulation of citric acid from the submerged basal medium, of whichASHUS 1 significantly (?<0.05) recorded the most yield from the production after 9 days ofincubation.

Exploring the mechanism of citric acid for treating glucose metabolism disorder induced by hyperlipidemia.

Citric acid is a crucial organic in our daily life. The effect and mechanism of citric acid on glucose metabolism disorder induced by hyperlipidemia were explored by hyperlipidemic rat models which were established and treated with Xuezhikang and citric acid for 40 days. The results showed that citric acid significantly decreased liver index and reduced levels of triglyceride, total cholesterol and low-density lipoprotein cholesterol, while increasing high-density lipoprotein cholesterol. And citric acid observably decreased blood glucose and insulin resistance index, as well as increasing insulin sensitivity. Meanwhile, citric acid dramatically down-regulated mRNA and protein expression levels of glucose-6-phosphatase (G-6-Pase) (p < .01) and up-regulated those of glucose transporter 4 (GLUT-4) (p < .01). And significantly increased the contents of acetic, propionic and butyric acids (p < .01). These findings suggest that citric acid can regulate blood lipid levels in hyperlipidemic rats, reduce the resistance induced by hyperlipidemia, and improve insulin sensitivity. PRACTICAL APPLICATIONS: These findings suggest that citric acid can regulate blood lipid levels in hyperlipidemic rats, reduce the resistance induced by hyperlipidemia, and improve insulin sensitivity. and provide a theoretical basis for the application of citric acid in diseases related to glucose metabolism disorders.

Effect of Citric Acid and Mowing on Enhancing the Remediation of Cadmium Contaminated Soil by Napier Grass (Pennisetum purpureum Schum)

A pot experiment was conducted to investigate the effects of citric acid application and mowing frequency on the remediation of cadmium (Cd) contaminated soil by napier grass (Pennisetum purpureum Schum). Three levels of citric acid were divided into three applications of 1.25, 2.5, and 5 mmol·kg-1. The mowing frequency of the plants was divided into no mowing, one mowing, and two mowing treatments. The results showed that:① 1.25 mmol·kg-1 citric acid increased the biomass of the upper part of the plant by 39.11% with one mowing, and multiple mowing treatments and high citric acid application were not beneficial to the biomass increase. ② Both citric acid application and mowing had the effect of increasing the Cd content in stems and leaves, and Cd content in stems harvested in the last mown crop was larger and increased by approximately six times under the 5 mmol·kg-1 citric acid application. ③ Citric acid application and mowing reduced the rhizosphere soil pH and organic matter and also reduced the total soil Cd content and TCLP-Cd content by a maximum of 14.29% and 10.17%, respectively. ④ Under the 1.25 mmol·kg-1citric acid application and one mowing treatment (L1), the best Cd extraction by Napier grass was achieved with 6.95 mg·plant-1 of above-ground parts, accounting for 9.38% of the total Cd content in the potted test soil. Therefore, the L1 treatment can be considered to improve the remediation efficiency when using napier grass to remediate Cd-contaminated soil in the future.

Influence of eight debridement techniques on three different titanium surfaces: A laboratory study.

Debridement methods may damage implant surfaces. This in vitro study investigated eight debridement protocols across three implant surfaces to assess both biofilm removal and surface alterations. One hundred sixty commercially pure titanium discs were treated to simulate commercially available titanium implant surfaces-smooth, abraded and abraded and etched. Following inoculation with whole human saliva to create a mixed species biofilm, the surfaces were treated with eight debridement methods currently used for clinical peri-implantitis (n=10). This included air abrasion using powders of glycine, sodium bicarbonate and calcium carbonate; conventional mechanical methods-piezoelectric scaler, carbon and stainless steel scalers; and a chemical protocol using 40% citric acid. Following treatment, remaining biofilm was analysed using scanning electron microscopy and crystal violet assays. For statistical analysis, ANOVA was applied (p < 0.05). All debridement techniques resulted in greater than 80% reduction in biofilm compared with baseline, irrespective of the surface type. Glycine powder delivered through an air polishing system eliminated the most biofilm. Mechanical instruments were the least effective at eliminating biofilm across all surfaces and caused the greatest surface alterations. Citric acid was comparable with mechanical debridement instruments in terms of biofilm removal efficacy. Titanium surfaces were least affected by air abrasion protocols and most affected by mechanical methods. Mechanical protocols for non-surgical debridement should be approached with caution. Glycine powder in an air polisher and 40% citric acid application both gave minimal alterations across all implant surfaces, with glycine the superior method in terms of biofilm removal.