Heavy metals tolerance in bacteria from industrial wastewater

The incidence of chemical stressors in industrial waste effluents has culminated in the re-engineering the genetic and metabolic characteristic of resident microbiota. Microbial adaptability enables them to tolerate these stressors however, propelling the phenomena of acquisition of heavy metal resistance which may also incite resistance to antibiotics. Waste water from industrial establishments may travel from site into surrounding communities via canals and waterways thus, disseminating these stressors as well as resistance in the environment. This study seeks to investigate the physicochemical and heavy metal composition of industrial effluent and its tolerance in resilient bacteria from the study area. Physiochemical analyses revealed pH level which ranged between (5.8-10.87), BOD (6.612-16.01 mg/l), TDS (937.226-2173.49 mg/l), Sulphates (658.72- 1342.28 mg/l), Nitrates (11.46-70.16 mg/l), Phosphate (3.03-8.43 mg/l) exceeded the NESRA limits; Cu (0.024-4.521 mg/l) Cd (0.002-6.41 mg/l), Pb (0.001-8.151mg/l), Zn (0.511-6.092 mg/l). All the isolates showed marked tolerance to Cu, Cr, Pb, Cd and Zn at concentrations between 200 and 500µg/ml, except Alkanindiges sp. 5-0-9 and Bacillus altitudinis which were not susceptible to all the heavy metals at all concentrations. This study revealed the incidence of heavy metal resistance among bacterial isolates from industrial wastewater, the incidence of which could give rise to co-occurrence with antibiotic resistance thus, aggravating a public health concern.

ASSESSMENT OF HEAVY METALS TOLERANCE OF BACTERIAL ISOLATES FROM EFFLUENT OF METAL PROCESSING INDUSTRIES

In this study heavy metals tolerance of bacterial isolates from efuent of metal processing industries was carried out. The microbiological analysis total of 6 industrial efuents samples were collected from various industries, and total of 42 isolates were obtained among these isolates were screed for heavy metals tolerance/resistance, among them one isolate SR6a (Achromobactor) was resistant to Cu at higher concentration (2000ppm) and considered as potential heavy metal resistance isolate. The some isolates such SR3f (Bacillus), SR4g (Achromobactor), SR5c (Bacillus), and SR3a (Pseudomonas) were multi heavy metal resistance ones. All these isolates from metal industrial efuents showed the heavy metal resistance against Copper, Nickel, Cadmium, Zinc and Mercury. the isolate SR6a identied as Achromobactor sp. was able to tolerate the heavy metal up to 3000 ppm concentration and can be very useful for the application in the environmental bioremediation.

Endomembrane Reorganization Induced by Heavy Metals

Plant cells maintain plasmatic concentrations of essential heavy metal ions, such as iron, zinc, and copper, within the optimal functional range. To do so, several molecular mechanisms have to be committed to maintain concentrations of non-essential heavy metals and metalloids, such as cadmium, mercury and arsenic below their toxicity threshold levels. Compartmentalization is central to heavy metals homeostasis and secretory compartments, finely interconnected by traffic mechanisms, are determinant. Endomembrane reorganization can have unexpected effects on heavy metals tolerance altering in a complex way membrane permeability, storage, and detoxification ability beyond gene’s expression regulation. The full understanding of endomembrane role is propaedeutic to the comprehension of translocation and hyper-accumulation mechanisms and their applicative employment. It is evident that further studies on dynamic localization of these and many more proteins may significantly contribute to the understanding of heavy metals tolerance mechanisms. The aim of this review is to provide an overview about the endomembrane alterations involved in heavy metals compartmentalization and tolerance in plants.

Mechanism of Heavy Metal ATPase (HMA2, HMA3 and HMA4) Genes

Heavy metals are the most important pollutants that are non-biodegradable and increasingly accumulate in the environment. Phytoremediation can be defined as the use of plants for the extraction, immobilization, containment, or degradation of contaminants. It provides an ecologically, environmentally sound and safe method for restoration and remediation of contaminated land. Plant species vary in their capacity of hyper-accumulation of heavy metals. The chapter reviews the current findings on the molecular mechanism involved in heavy metals tolerance, which is a valuable tool for phytoremediation. The heavy metal tolerance genes help in the hyper-accumulation trait of a plant. Heavy metal transporter ATPases (HMAs) genes help in the refluxing of heavy metal ions from the cytosol, either into the apoplast, the vacuole, or other organelles, which help in the hyperaccumulation of metal. Understanding the signaling mechanism of transporter genes will be an important tool to understand the genetics of hyperaccumulation.