Biosorbents for heavy metals removal and their future

Objective(s): Gallic acid is a natural phenolic compound found in several fruits and medicinal plants. It is reported to have several health-promoting effects. This review aims to summarize the pharmacological and biological activities of gallic acid in vitro and animal models to depict the pharmacological status of this compound for future studies.Materials and Methods: All relevant papers in the English language were collected up to June 2018. The keywords of gallic acid, antioxidant, anticancer, antimicrobial, gastrointestinal-, cardiovascular-, metabolic-, neuropsychological-, and miscellaneous- diseases were searched in Google Scholar, PubMed, and Scopus.Results: Several beneficial effects are reported for gallic acid, including antioxidant, anti-inflammatory, and antineoplastic properties. This compound has been reported to have therapeutic activities in gastrointestinal, neuropsychological, metabolic, and cardiovascular disorders. Conclusion: Current evidence confirms the pharmacological and therapeutic interventions of gallic acid in multiple health complications; however, available data are limited to just cellular and animal studies. Future investigations are essential to further define the safety and therapeutic efficacy of gallic acid in humans.

https://ijbms.mums.ac.ir/article_12251_1e2b9a1363690fd784d6b16a6d3a5d5a.pdf

Pharmacological effects of gallic acid in health and diseases: A mechanistic review.

Dyes used in the coloration of textiles, paper, and other products are highly visible, sometimes toxic, and sometimes resistant to biological breakdown; thus it is important to minimize their release into aqueous environments. This review article considers how biosorption of dyes onto cellulose-related materials has the potential to address such concerns. Numerous publications have described how a variety of biomass-derived substrates can be used to absorb different classes of dyestuff from dilute aqueous solutions. Progress also has been achieved in understanding the thermodynamics, kinetics, and chemical factors that control the uptake of dyes. Important questions remain to be more fully investigated, such as those involving the full life-cycle of cellulosic substrates that are used for the collection of dyes. Also, more work needs to be done in order to establish whether biosorption should be implemented as a separate unit operation, or whether it ought to be integrated with other water treatment technologies, including the enzymatic breakdown of chromophores.

https://ojs.cnr.ncsu.edu/index.php/BioRes/article/download/BioRes_06_2_2161_Hubbe_HD_Removal_Pollutants_Review_Pt1_Metals/1901

Cellulosic substrates for removal of pollutants from aqueous systems: a review. 1. metals

Biodegradation is defined as the biologically catalyzed reduction in complexity of chemical compounds [1]. Indeed, biodegradation is the process by which organic substances are broken down into smaller compounds by living microbial organisms [2]. When biodegradation is complete, the process is called "mineralization". However, in most cases the term biodegra‐ dation is generally used to describe almost any biologically mediated change in a substrate [3].

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Biodegradation: Involved Microorganisms and Genetically Engineered Microorganisms

Due to exponential expansion of human population and in turn, incessant intensification in industrialization, heavy metal pollution has become ubiquitous from air to deep soil. There are many bioremediation technologies including biosorption process to decontaminate the heavy metal polluted sites. Currently, the exploitation of microbial biosorption of heavy metals is considered a reliable alternative over the conventional bioremediation approaches. Fundamentally, biosorption is the chemical or physical interaction between biosorbent (solid phase e.g. biomass) and chemical species (e.g. heavy metals) in liquid phase. Application of microorganisms (specifically bacteria, algae, yeasts and fungi) as biosorbents for heavy metal removal have received growing interest due to the high surface to volume ratio, large availability, rapid kinetics of adsorption and desorption and little cost. The present review highlights the underlying features of biosorption, recent updates in mechanisms and selection of biosorbents and various factors affecting biosorption.

Recent Trends in Microbial Biosorption of Heavy Metals: A Review

\n Food quality and safety are the two important factors that have gained ever-increasing attention in general consumers. Conventionally grown foods have immense adverse health effects due to the presence of higher pesticide residue, more nitrate, heavy metals, hormones, antibiotic residue, and also genetically modified organisms. Moreover, conventionally grown foods are less nutritious and contain lesser amounts of protective antioxidants. In the quest for safer food, the demand for organically grown foods has increased during the last decades due to their probable health benefits and food safety concerns. Organic food production is defined as cultivation without the application of chemical fertilizers and synthetic pesticides or genetically modified organisms, growth hormones, and antibiotics. The popularity of organically grown foods is increasing day by day owing to their nutritional and health benefits. Organic farming also protects the environment and has a greater socio-economic impact on a nation. India is a country that is bestowed with indigenous skills and potentiality for growth in organic agriculture. Although India was far behind in the adoption of organic farming due to several reasons, presently it has achieved rapid growth in organic agriculture and now becomes one of the largest organic producers in the world. Therefore, organic farming has a great impact on the health of a nation like India by ensuring sustainable development.

/pdf/organic-farming-in-india-a-vision-towards-a-healthy-nation-22fb2pa8go.pdf

Organic farming in India: a vision towards a healthy nation

A cadmium tolerant strain of Aspergillus niger and a lead tolerant strain of Rhizopus arrhizus were studied for distribution of accumulated toxic heavy metals in the mycelia in comparison to wild type strains. Accumulated cadmium in the cell wall fract ions of cadmium tolerant Aspergillus niger was more than the wild type strain. Cytosolic fraction conta ined the next highest load of metal. Similar was th e observation with lead tolerant Rhizopus arrhizus during bioaccumulation of lead. The results indica ted contribution of the surface property of the fungus in metal bioaccumulation. Involvement of the cellul ar metabolism during metal bioaccumulation and distribution in the sub-cellular compartments was substantiated by the use of some metabolic inhibito rs during growth in presence of metals. It was also observed that about 65% of the cell wall bound cadmium in Aspergillus niger and about 79% of the cell wall bound lead in Rhizopus arrhizus were recovered by Ethylene diamine tetra acetic aci d (EDTA) treatment, which indicated that the accumulated met als generally reside in the outer surface of the fu ngi, which could be recovered easily for possible commercial applications.

Cellular Distribution of Bioaccumulated Toxic Heavy Metals in Aspergillus Niger and Rhizopus Arrhizus

Saraca indica has been greatly used as traditional medicine for women related problems, such as leucorrhoea, menorrhagia, dysfunctional uterine bleeding, bleeding haemorrhoids etc. In this study different Phytochemicals and free radical scavenging activity were measured in the ethanolic and water extract of fresh and dried flowers of Saraca indica collected from in and around Barrack pore area, West Bengal. The Phytochemicals studied from flower extracts are total polyphenols, flavonoids, ascorbic acid and tannins. Free Radical scavenging activities of the extracts were evaluated using DPPH assay method. The results revealed that total polyphenols, flavonoids and tannins content were relatively higher in ethanolic extract of the fresh flower and water extract of the dried flower of Saraca indica. Whereas both extract of dried flower contained higher amount of ascorbic acid. The free radical scavenging activity was higher in fresh flower extract (both ethanol and water) in comparison to dried flower. The results revealed that the antioxidant property of both flower extracts may improved human health status and stay away from many diseases.

https://www.ijcmas.com/vol-3-4/Tapan%20Kumar%20Pal,%20et%20al.pdf

Evaluation of antioxidant activities of flower extract (fresh and dried) of Saraca indica grown in West Bengal.

Biosorption of heavy metals by Rhizopus arrhizus and Aspergillus niger

Tea (Camelia sinensis) is the most consumed beverage and is also known for its medicinal value. Tea plants grown at higher altitude are subject to enhanced oxidative stress due to high UV radiation, climatic changes, and soil conditions, compared to places at low altitude. The present study was undertaken to find out whether the antioxidant activity and the content of bioactives change with the variations of altitudes in a district of Darjeeling, where tea is cultivated most. The samples were collected from six different altitudes of Darjeeling hill, viz. 6900, 5800, 4500, 3600, 2500 and 500 feet. The assays performed included ABTS radical cation decolorization assay, DPPH radical decolorization assay, reducing power assay, total polyphenols content, tannin content and total flavonoid content. It was observed that ABTS and DPPH radical scavenging abilities were reduced with increasing altitude, suggesting probable depletion of the antioxidant bioactives on exposure to extreme climatic conditions as well as elevated UV radiations. However, changes in the major bioactives of tea like tannins and flavonoids with altitude were non-significant, suggesting that although the plant tries to cope up with extreme climatic conditions, its medicinal value remains almost unchanged with altitude.

/pdf/evaluation-of-in-vitro-antioxidant-potential-of-tea-camelia-2t5vbzsbus.pdf

Tapan Kumar Pal

Papers

Organic farming in India: a vision towards a healthy nation

Cellular Distribution of Bioaccumulated Toxic Heavy Metals in Aspergillus Niger and Rhizopus Arrhizus

Evaluation of antioxidant activities of flower extract (fresh and dried) of Saraca indica grown in West Bengal.

Biosorption of heavy metals by Rhizopus arrhizus and Aspergillus niger

Evaluation of in vitro antioxidant potential of Tea (Camelia sinensis) leaves obtained from different heights of Darjeeling Hill, West Bengal -