Heavy metal and pesticide pollution have become an inevitable part of the modern industrialized environment that find their way into all ecosystems. Because of their persistent nature, recalcitrance, high toxicity and biological enrichment, metal and pesticide pollution has threatened the stability of the environment as well as the health of living beings. Due to the environmental persistence of heavy metals and pesticides, they get accumulated in the environs and consequently lead to food chain contamination. Therefore, remediation of heavy metals and pesticide contaminations needs to be addressed as a high priority. Various physico-chemical approaches have been employed for this purpose, but they have significant drawbacks such as high expenses, high labor, alteration in soil properties, disruption of native soil microflora and generation of toxic by-products. Researchers worldwide are focusing on bioremediation strategies to overcome this multifaceted problem, i.e., the removal, immobilization and detoxification of pesticides and heavy metals, in the most efficient and cost-effective ways. For a period of millions of evolutionary years, microorganisms have become resistant to intoxicants and have developed the capability to remediate heavy metal ions and pesticides, and as a result, they have helped in the restoration of the natural state of degraded environs with long term environmental benefits. Keeping in view the environmental and health concerns imposed by heavy metals and pesticides in our society, we aimed to present a generalized picture of the bioremediation capacity of microorganisms. We explore the use of bacteria, fungi, algae and genetically engineered microbes for the remediation of both metals and pesticides. This review summarizes the major detoxification pathways and bioremediation technologies; in addition to that, a brief account is given of molecular approaches such as systemic biology, gene editing and omics that have enhanced the bioremediation process and widened its microbiological techniques toward the remediation of heavy metals and pesticides.
1 The effect on platelet functions of dipyridamole (a pyrimido‐ pyrimidine compound) was compared with a control group of patients taking warfarin. 2 Adhesion, aggregation and platelet factor 4 availability showed a significant decrease in the dypyridamole group. 3 Aggregation and platelet factor 4 showed a significant correlation with blood dipyridamole level. 4 Adhesion, aggregation and platelet factor 4 were reduced below the lower limit of normal at blood dipyridamole levels above 3.5 micronmol/1.
Cinnamon stick is world widely used in cooking, traditional medicine, perfumery and aesthetic industries. Many studies have demonstrated the potential of cinnamon extracts in diabetes treatment. Although it has been reported as safe in general cooking recipe and categorized as GRAS by USDA, sub-acute toxicity procedure was conducted in this study to determine the effect of cinnamon extract on histopathological changes as well as the haematological parameters of blood. Water extraction was done for dried cinnamon. Twenty-four female Sprague Dawley rats were used in this study. The oral route was selected because it is the most likely route of human exposure through the consumption of herbs. The concentrations studied were 0.1, 0.5 and 2.0g/kg cinnamon aqueous extract (CE). There were no statistically significant effects of all concentrations of CE on behaviour, mortality, water intake, food consumption, weight gain, internal organs weight (liver and kidney) and heamatological parameters during treatment and post-treatment periods except: 1) the slight decreased in kidney and liver weight of rats treated with 0.5g/kg and 2) slight decreased in liver weight of rats treated with 2.0g/kg, during post-treatment period. Hence, these toxicity studies suggest that the CE is low to moderate in toxicity and CE below 0.5 g/kg dose level is safe to be used in the efficacy study especially for diabetes treatment.
Maltogenic amylase (Mag1) is a potent enzyme that hydrolyzes the glycosidic bond of polysaccharides to produce malto-oligosaccharides (MOS). However, the Mag1 enzyme has poor stability and reusability, leading to inefficient MOS production. Enzyme immobilization is a promising method to solve the enzyme stability problem. Entrapment and encapsulation technique was used in this study to immobilize Mag1 because of high biocompatibility and prevention of enzyme degradation, hence lesser loss of enzymatic activity. Chitosan was used as a coating membrane on the alginate matrix, preventing enzyme leaching from the beads. Mag1 entrapped in alginate-chitosan beads showed better performance compared to alginate beads in terms of thermostability, reusability and enzyme retention. Alginate-chitosan beads showed improvement of temperature stability of approximately 35%, 30% and 20% at a respective temperature of 30 °C, 40 °C and 50 °C. Reusability analysis showed immobilized Mag1 can be used up to at least eight cycles with retained activity of 80% and 70% from its initial activity for alginate-chitosan and alginate beads respectively. Enzyme leakage percentage in alginate-chitosan was 7-21%, while that in alginate was 12-35%. The overall findings envisage the promising application of alginate-chitosan beads immobilized Mag1 as a biocatalyst for MOS synthesis.
Maltogenic amylase is one of the significant enzymes in oligosaccharides synthesis. Its ability to utilise multiple substrates and catalyse hydrolysis and transglycosylation reactions simultaneously makes it a unique biocatalyst. The catalysis could be exploited in many ways to obtain oligosaccharides of different lengths and various modified sugars. Nonetheless, one of the major drawbacks of substrate hydrolysis to produce oligosaccharides is the low production of MOS with higher degree of polymerisation. To address this issue, reaction parameter optimisation was performed via one-factor-at-a-time (OFAT) approach on the production of MOS from soluble starch hydrolysis using maltogenic amylase from Bacillus lehensis G1 (MAG1). Optimisation of MAG1 loading, soluble starch loading, temperature, time and pH resulted in the production of 84.87 mg/g MOS with polymerisation degree of 3 to 7 compared to that of 51.60 mg/g obtained before the optimisation process, which recorded 1.64-fold increment. Among all parameters, soluble starch loading gave the most significant impact on the MOS production as the reaction equilibrium is highly affected by substrate concentration. The occurrence of MOS with polymerisation degree of 4 and above, which resulted from starch hydrolysis further confirms the endo-type of MAG1. Because starch is an abundant and inexpensive source of carbohydrate in the world, this study provides a cost-effective MOS production process which is highly relevant for industry.
In this report, one herbal folk recipe traditional claim for diabetes treatment, jamu KM is subjected to scientific studies. The exposure of traditional diabetes decoction, KM extract to 3T3-L1 at 1 mg mL shows significant increase in glucose uptake with no LD value. 150 μg mL methanolic extract of Jamu KM yield intense lipid droplet accumulation in non-insulin induced adipocytes 3T3-L1. Further investigation through in vivo study of KM extract using diabetic Spraque Dawley rats indicates reduction in blood glucose at the concentration of 0.05 g kg body weight (bwt). A similar response was observed with the treatment using glibenclamide at 0.006 g kg bwt. Histopathological data show increase in the relative organ weight (g 100 g bwt) of liver and kidney of all diabetic rats as compared to normal group while pancreas was not affected. However, glibenclamide treated group shows 14 and 15% larger liver and kidney, respectively, than the other diabetic groups and jamu KM treated. This finding is a promising approach in validation of herbal medication from the past wisdom through modern techniques.
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