2023

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Browsing 2023 by Author "Mahnoor"

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    Heavy Metal Resistant Purple Non-Sulfur Bacteria Isolated from Local Pond in Lahore
    (UMT, Lhr, 2023) Mahnoor
    Purple non sulfur bacteria are phototrophic bacteria belonging to the group Proteobacteria. PNSB give reddish brown to purple color when grown in anaerobic conditions and incandescent light. PNSB are known to possess diverse metabolic activities and hence are of great biotechnological interest. Heavy metals such as arsenic, mercury, cadmium, chromium and nickel are toxic for the environment and can cause many health-related problems. PNSB can help in the detoxification of heavy metals from the environment. In this study, PNSB were isolated from different ponds located in Model town park and from a pond located near Kot Lakhpat jail in Quaid-e-Azam industrial state, Lahore. PNSB were screened for resistance against different toxic metals. The process of characterizing and identifying PNSB combined morphological, biochemical, physiological, and molecular methods. These PNSB isolates were gram negative. To better define PNSB, several physiological tests can be carried out. When PNSB growth was investigated at various pH values and temperatures, all isolates were able to grow at 25 to 40℃, however, maximum growth occurred at 30 and 37℃. PNSB generate pigments including bacteriochlorophylls and carotenoids, which gives them their purple shade. The pigmentation of all PNSB isolates was reddish brown to purple shade. The hydrogen gas generated by PNSB photosynthesis is a clean and renewable energy. For every PNSB isolate, the gas generation experiment was carried out. With the exception of MNP2, MNP4, and MNP7, all outcomes were positive. PNSB were analyzed for resistance against different concentrations of arsenic, cadmium, mercury, chromium and nickel. The maximum concentration of arsenate, arsenite, chromium, cadmium, mercury and nickel resisted by PNSB were 40mM for arsenate, 10mM for arsenite, 5mM for chromium, 2.5mM for cadmium, 2.5 mM for mercury and 5mM for nickel. Growth curve pattern of PNSB was analyzed both in absence and presence of arsenic. The phylogenetic connection of PNSB species is frequently ascertained using 16S rRNA gene sequencing. Genomic DNA was isolated and 16S rRNA gene was amplified using PCR. The amplicons were sequenced from Macrogen, Korea. These PNSB can be utilized to detoxify arsenic along with production of hydrogen.