Heavy metal pollution generally occurs due to socio-economic, industrial, and anthropogenic activities, which may cause an environmentally hazardous and serious severe threat to the survival of the organisms (genotoxic, carcinogenic, and clastogenic effects on it). Many physical and chemical remediation approaches have been proposed to deal with this pollution, but these are very time-consuming and costly. While bioremediation stands out as an inexpensive and efficient approach, the use of bacteria is thought to be a potential and productive organism to prevent this pollution. This review has evaluated the bacterial potential to clean up heavy metals from the environment and elucidated the mechanisms responsible for bioremediation.

Food spoilage is an undesirable process and is a serious problem for humans. There are many factors that accelerate and affect food spoilage. In this study, microbial behaviors in foods, microorganisms causing food spoilage and beneficial microorganisms are mentioned.

Bacterial pathogens are isolated, identified and antibiogram were performed by taking the skin, gills and intestine of twenty randomly selected Tilapia fish (Oreochromis niloticus) that collected from local market of the Dinajpur city, Bangladesh. A serial dilution was prepared with the stated sample and at the amount of 0.1 ml was plated on nutrient agar, differential also specific media respectively. Then gram’s staining, colony morphology, biochemical test and antibiogram performed respectively. The four different isolated species with frequency of occurrence are 31(40.26%) Escherichia coli, 3 (29.87%) Staphylococcus spp., 13 (16.88%) Pseudomonas spp., 10 (12.99%) Salmonella spp. respectively. Some of these pathogens have tendency to transmit to man, who eat fish or deal with fish and fish products. Amoxicillin, Cefixime, Azithromycin, Chloramphenicol, Ciprofloxacin, Penicillin G, Erythromycin, Vancomycin, Gentamicin and Neomycin antibiotics was performed during sensitivity test. Among the total (77) isolated bacteria were sensitive to gentamycin, chloramphenicol, ciprofloxacin and Azithromycin but resistant to Amoxicillin, Penicillin G, Vancomycin and Erythromycin. The study was conducted in term of medical importance. Hence it is considered that a variety of bacterial species can be associated with fresh Tilapia fish related pathogen to humans.

Molecular approaches used to identify bacterial species use 16S rRNA and MLST to determine the genetic linkage of bacteria; MLST characterizes clonal linkages by examining differences in various gene loci. MLVA determines the genetic relationships of bacterial strains and biovar-level differences and assesses the copy number of repeated DNA sequences. Sequencing provides genetic data by identifying DNA sequences; Sanger sequencing is the basis for next-generation approaches. CRISPR modifies the genetic code and can correct mutations or control genes using Cas9. These methods are important for identifying bacterial species and annotating genomic information. The methods used for this purpose are brought together in this study. The explanation and detailed description of the methods examined will contribute to their use in the field of microbiology.

Global climate is estimated to change drastically over the next century and the ecosystems will be affected in this changing environment. Plant-associated beneficial microorganisms can stimulate plant growth and increase resistance to biotic and abiotic stresses. Nowadays, the effects of climate change factors such as increased carbon dioxide (CO2), drought and warming on plant-beneficial microorganism interactions are increasingly being investigated in the scope of plant growth and health. Recent studies have shown that high CO2 level has a positive effect on the abundance of mycorrhizal fungi, whereas the effects on plant growth promoting bacteria and endophytic fungi are more variable. Elevated CO2 conditions lead to increased colonization of beneficial fungi. Additionally, the results of increasing CO2 levels, warming and drought, depend upon the plant and the microbial genotype. Also, plant growth promoting microorganisms, especially bacteria, positively affect plants exposed to drought stress. Altered communities of beneficial microorganisms depending on climate changes, might have to compete with different microbial communities and, therefore microbial activities may also get affected. This work presents that climate change is an important factor affecting microorganism and plant interactions, needs to take into consideration the adaptation processes in plants and microorganisms and might require the selection of adapted plant cultivars.