Potential use of composts and vermicomposts as low-cost adsorbents for dye removal: an overlooked application

The use of composts and vermicomposts as adsorbents is an important topic of study in the field of environmental remediation. These materials are rich in organic matter and have functional groups that can interact with organic and inorganic compounds. They also contain microorganisms that can promote biodegradation of organic substances. Composts that cannot be used for agronomic purposes (owing to e.g. low nutrient levels or phytotoxicity) may be valuable for soil remediation or pollutant removal. In this review, we discuss papers on this topic, with the objective of drawing attention to the potential use of composts/vermicomposts and to recommend further investigation on this subject. Few published studies have investigated the use of composts/vermicomposts to remove dyes and other coloured compounds. However, preliminary results show that these materials are potentially good adsorbents, at least comparable to other low-cost adsorbents, and that, in general, basic dyes are more efficiently removed than direct, reactive or acid dyes. The results of the works reviewed also show that dye removal takes place by adsorption mechanisms, in most studies following a Langmuir model, and that the kinetics of removal are fast and follow a pseudo-second order model. However, there remain several uncertainties regarding this application. For example, very few dyes have been studied so far, and little is known about the influence of the properties of composts/vermicomposts on the dye removal process. Moreover, the possible use of compost/vermicompost to enhance biodegradation processes has not been explored. All these questions should be addressed in future research.Postprint (author's final draft

Industrial symbiosis between the winery and environmental industry through the Utilization of grape marc for water desalination containing copper(II)

A bioadsorbent formulated with a secondary raw material, consisting of grape marc, subjected to a bioxidize process and entrapped in calcium alginate beads, was used for the desalination of water containing copper(II) sulfate. Experiments were established under different experimental conditions varying the concentration of contaminant, the amount of bioadsorbent, and the extraction time through response surface methodology. The most significant variable in the removal of copper(II) sulfate was the amount of bioadsorbent employed, followed by the extraction time; whereas, the adsorbent capacity was more influenced by the amount of contaminant and the amount of bioadsorbent used. At the highest concentration of copper(II) sulfate (0.15 mol/L), the equations obtained predict that the bioadsorbent has a capacity of 2785 mg/g and produces a copper(II) removal about 43% using low adsorbent/water ratios, 1:10 (v/v), and maximum extraction times; whereas, it would remove 97.2% of copper(II) sulfate in 5 min, using adsorbent/water ratios close to 1:2 (v/v), with capacity values, in this case, around 1800 mg/g. The encapsulation of the bioxidize adsorbent increased its capacity to 30% and allowed the precipitation of sulfate ions as calcium sulfate. The results obtained in this work could presume advances for promoting the industrial symbiosis between winery and environmental industries.Peer ReviewedPostprint (author's final draft

A Multifunctional biosurfactant extract obtained from corn steep water as bactericide for agrifood industry

The increase of crop production along with stricter requirements on food security have augmented the demand of new and eco-friendly bactericides. Most of the bactericides used at the moment consist of persistent organic substances, representing a risk for environmental and human health. For instance, agriculture bactericides used for crop protection includes copper-based, dithiocarbamate and amide bactericides, which are not biodegradable, resulting in the necessity of further research about the production of new active principles that attack microorganisms without producing any harmful effect on human health or environment. The biosurfactant extract evaluated in this work as a bactericide, is obtained from corn steep water, a residual stream of corn wet milling industry, which is fermented spontaneously by probiotic lactic acid bacteria that possess the capacity to produce biosurfactants. In previous works, it has been demonstrated that this biosurfactant extract is able to promote the growth of Lactobacillus casei in drinkable yogurts, though its antimicrobial activity against pathogenic strains has not been evaluated at the moment. The results obtained in this work have proved that this biosurfactant extract is effective as bactericide against Pseudomonas aeruginosa and Escherichia coli, at concentrations of 1 mg/mL, opening the door to its use in agrifood formulations for reducing the use of chemical pesticides and preservatives.Postprint (author's final draft

Biological surfactants vs. polysorbates: Comparison of their emulsifier and surfactant properties

In this work two biological surfactants, a cell-bound biosurfactant produced by Lactobacillus pentosus and a biosurfactant obtained from a fermented stream corn milling industry, were compared with two chemical surfactants (polysorbate 20 and polysorbate 80) in terms of surface tension reduction, critical micellar concentration (CMC), oil spreading and emulsifying capacity. Biological surfactants showed a similar ability to reduce the surface tension of water as polysorbates, which was in conformance with the results obtained in the drop collapse test. Regarding the ability to spread the oil on water, both biosurfactants produced similar results as polysorbates after 1 h. However, after 24 h, polysorbates and biosurfactant from corn stream were more effective than L. pentosus biosurfactant, producing greater free oil areas. Concerning the emulsifying activity, in terms of relative emulsion volume (EV), the biosurfactant produced from L. pentosus gave the best results (EV = 100%), after 1 day of emulsion formation, keeping this value over 50% after 15 days of emulsion formation; whereas polysorbates gave EV values lower than 50%. The CMC values of the biosurfactant from corn stream and of polysorbates were closer in comparison with the CMC value of L. pentosus biosurfactant, observing that the characteristics and properties of the biosurfactant from corn stream are more similar to polysorbates than to L. pentosus biosurfactant. Thus, it could be speculated that biosurfactant from corn stream would be a good substitute for polysorbatesPeer ReviewedPostprint (published version

Potential use of composts and vermicomposts as low-cost adsorbents for dye removal: an overlooked application

The use of composts and vermicomposts as adsorbents is an important topic of study in the field of environmental remediation. These materials are rich in organic matter and have functional groups that can interact with organic and inorganic compounds. They also contain microorganisms that can promote biodegradation of organic substances. Composts that cannot be used for agronomic purposes (owing to e.g. low nutrient levels or phytotoxicity) may be valuable for soil remediation or pollutant removal. In this review, we discuss papers on this topic, with the objective of drawing attention to the potential use of composts/vermicomposts and to recommend further investigation on this subject. Few published studies have investigated the use of composts/vermicomposts to remove dyes and other coloured compounds. However, preliminary results show that these materials are potentially good adsorbents, at least comparable to other low-cost adsorbents, and that, in general, basic dyes are more efficiently removed than direct, reactive or acid dyes. The results of the works reviewed also show that dye removal takes place by adsorption mechanisms, in most studies following a Langmuir model, and that the kinetics of removal are fast and follow a pseudo-second order model. However, there remain several uncertainties regarding this application. For example, very few dyes have been studied so far, and little is known about the influence of the properties of composts/vermicomposts on the dye removal process. Moreover, the possible use of compost/vermicompost to enhance biodegradation processes has not been explored. All these questions should be addressed in future research

Study of the synergic effect between mica and biosurfactant to stabilize Pickering emulsions containing Vitamin E using a triangular design

Hypothesis Vitamin E has interesting biological functions for the cosmetic and pharmaceutical industry because it can act as a fat-soluble antioxidant, as well as peroxyl radical scavenger. However, this vitamin is formed by a group of compounds that include tocopherols (¿-tocopherols, a-tocopherol) characterized by their poor solubility in water, what implies the need of using stabilizing agents such as biosurfactants or minerals, in order to make them soluble or stable in formulations composed by water and oil. Experiments In this work, it has been evaluated the synergic effect between a mining silicate mineral (mica) and a biosurfactant extract, obtained from corn steep liquor, to stabilize emulsions containing water and a non-aqueous soluble antioxidant consisting of Vitamin E, through the use of a triangular design. Findings The results show that the presence of biosurfactant extract improves the emulsion volume up to 70% after 22¿days, for an emulsion composed of Vitamin E and biosurfactant, whereas the mica component was able to increase the emulsion stability until values of 80% after 30¿days of experiment, for those emulsions containing 10% of mica. Hence, both novel ingredients produce a synergistic effect on the Pickering emulsions carried out in the study.Peer Reviewe

Industrial symbiosis between the winery and environmental industry through the Utilization of grape marc for water desalination containing copper(II)

A bioadsorbent formulated with a secondary raw material, consisting of grape marc, subjected to a bioxidize process and entrapped in calcium alginate beads, was used for the desalination of water containing copper(II) sulfate. Experiments were established under different experimental conditions varying the concentration of contaminant, the amount of bioadsorbent, and the extraction time through response surface methodology. The most significant variable in the removal of copper(II) sulfate was the amount of bioadsorbent employed, followed by the extraction time; whereas, the adsorbent capacity was more influenced by the amount of contaminant and the amount of bioadsorbent used. At the highest concentration of copper(II) sulfate (0.15 mol/L), the equations obtained predict that the bioadsorbent has a capacity of 2785 mg/g and produces a copper(II) removal about 43% using low adsorbent/water ratios, 1:10 (v/v), and maximum extraction times; whereas, it would remove 97.2% of copper(II) sulfate in 5 min, using adsorbent/water ratios close to 1:2 (v/v), with capacity values, in this case, around 1800 mg/g. The encapsulation of the bioxidize adsorbent increased its capacity to 30% and allowed the precipitation of sulfate ions as calcium sulfate. The results obtained in this work could presume advances for promoting the industrial symbiosis between winery and environmental industries.Peer Reviewe

Biological surfactants vs. polysorbates: Comparison of their emulsifier and surfactant properties

In this work two biological surfactants, a cell-bound biosurfactant produced by Lactobacillus pentosus and a biosurfactant obtained from a fermented stream corn milling industry, were compared with two chemical surfactants (polysorbate 20 and polysorbate 80) in terms of surface tension reduction, critical micellar concentration (CMC), oil spreading and emulsifying capacity. Biological surfactants showed a similar ability to reduce the surface tension of water as polysorbates, which was in conformance with the results obtained in the drop collapse test. Regarding the ability to spread the oil on water, both biosurfactants produced similar results as polysorbates after 1 h. However, after 24 h, polysorbates and biosurfactant from corn stream were more effective than L. pentosus biosurfactant, producing greater free oil areas. Concerning the emulsifying activity, in terms of relative emulsion volume (EV), the biosurfactant produced from L. pentosus gave the best results (EV = 100%), after 1 day of emulsion formation, keeping this value over 50% after 15 days of emulsion formation; whereas polysorbates gave EV values lower than 50%. The CMC values of the biosurfactant from corn stream and of polysorbates were closer in comparison with the CMC value of L. pentosus biosurfactant, observing that the characteristics and properties of the biosurfactant from corn stream are more similar to polysorbates than to L. pentosus biosurfactant. Thus, it could be speculated that biosurfactant from corn stream would be a good substitute for polysorbatesPeer Reviewe

Design and characterization of greener sunscreen formulations based on mica powder and a biosurfactant extract

© 2018 Elsevier B.V. The mining industry produces an earth-derived silicate mineral, called mica, which is included in many cosmetic formulations. Mica minerals produce a shimmering effect on the skin and simultaneously provide physical protection against the harmful effects of the sun. On the other hand, the corn wet-milling industry produces an effluent that contains a natural extract with antioxidant and biosurfactant properties, which could possibly be used to increase the protective effect of mica minerals against ultraviolet light (UV light). In this study, we determined the sunscreen protection factor (SPF) of different biocomposites based on different mica minerals alone or mixed with a biosurfactant extract obtained from the corn industry. The SPF values of water-based formulations containing mica with and without the biosurfactant extract were determined by means of a standardized method in which the absorbance was determined at wavelengths between 290 and 320 nm. The SPF values obtained for the mica minerals in the absence of biosurfactant ranged between 0.2 and 11, and in some cases the addition of biosurfactant increased the SPF values of the micas by more than 2000%.Peer ReviewedPostprint (author's final draft

Potential application of a multifunctional biosurfactant extract obtained from corn as stabilizing agent of vitamin C in cosmetic formulations

Vitamin C is an essential nutrient for human health, which can be found in the epidermis, playing an important role in the collagen production and protection of the skin. However, humans cannot produce this vitamin, being necessary to include it in health care products. Moreover, vitamin C is easily degradable making quite difficult to keep it as L-ascorbic acid form during long time. Thus, cosmetic and pharmaceutical industries include dehydrated vitamin C in its formulations to prevent its degradation. Therefore, it must be rehydrated before use, leading to a tedious process. The aim of this work was to study the addition of a multifunctional biosurfactant extract (BS), obtained from corn wet-milling industry, to an aqueous solution of L-ascorbic acid (AA) in order to improve the stability of this vitamin. A Box-Behnken factorial design was established in order to predict the degradation of vitamin C, using as independent variables: the concentration of vitamin C, the concentration of BS and the storage time. This study allowed to obtain a theoretical equation that predicts the degradation of vitamin C in presence and absence of BS, which was quantified by high performance liquid chromatography (HPLC). The experimental results showed that the presence of BS can inhibit the degradation of vitamin C in water up to 58% after 14 days in comparison with the same assays in absence of biosurfactant. This work opens the door to the use of this BS as stabilizing agent of formulations containing unstable active principles like vitamin C.Peer ReviewedPostprint (author's final draft