Removal efficiency of Cr6+ by indigenous Pichia sp. isolated from textile factory effluent

Hanensula anomala isolated from the Berkeley Pit, Butte, MT, is a metal-specific extremophile

A yeast-like extremophile organism, Hansenula anomala, has been isolated from the superfund site the Berkeley Pit Lake in Butte, Montana. Studies demonstrate H. anomala growth in some of the known Berkeley Pit Lake solutes. Microbial growth dynamics under controlled conditions were compared of H. anomala for multiple metal concentrations. Each solute/metal was tested separately at previously reported concentrations on the geochemistry of the Berkeley Pit lake in the first 0.2 m in spring (pH 2.5). H. anomala grew well with sulfur (S), MgSO4, CaSO4, potassium chloride (KCl), and NaSO4 and was inhibited with FeSO4, MnSO4, CuSO4, AlSO4, or ZnSO4. With the addition of elemental S, growth was observed for FeSO4 indicating minimal growth rescue. PCR amplification of genomic DNA from the organism using known ribosomal primers indicates the strain to be ATCC8168 (CBS 5759). From this data, it can be concluded that H. anomala ATCC8168 from the Berkeley Pit is an extremophile that exhibits metal-specific growth.IMPORTANCELaboratory growth studies of a strain of Hansenula anomala from the Berkeley Pit have found the organism to be metal specific indicating some unique metabolism possibilities. These studies show that this strain is metal-dependent and provides information about the adaptable tolerance of organisms in superfund sites as well as giving a basis for future bioremediation development utilizing H. anomala.

Phycoremediation potential and agar yield of red macroalgae (Gracilaria corticata) against HEDP (hydroxyethylidene diphosphonic acid) and CAPB (cocoamidopropyl betaine) detergents and the heavy metal pollutants

The discharge of raw industrial, agricultural, and domestic wastes leads to an increase in heavy metal (HM) burden and detergents in aquatic environs, which can have destructive effects on aquatic organisms. Agarophyte Gracilaria corticata, a major component of seaweed flora of the southern coast of Iran (Bushehr) that contains agar and red pigments, is one of the economically valuable red marine algae. Agar is one of the important polysaccharides with high economic value, widely used in pharmaceutical, medicinal, and cosmetic product manufacturing industries. The aim of this work was to investigate the effect of 5 HMs and two common surfactants in household and industrial detergents on the agar yield, appearance color, and the red algae's phycoremediation potential against HMs. The metal ions were Zn(II), Cu(II), Ni(II), Mn(II), and Cr(VI), and the surfactants were HEDP and CAPB. The analysis results of samples cultured for 60 days in seawater and polluted environments showed that G. corticata can accumulate copper and nickel. In the presence of detergents without HMs, the amount of extracted agar significantly increased compared to the control sample with no change in algae color. But with increasing concentration of HMs, the amount of agar in seaweed samples decreased significantly, and the algae discolored from red to dark green or yellowish-green color (signs of death in the algae). These results show that increasing of HM pollution and detergents can lead to toxicological effects and reduce the species diversity of red seaweeds in the future.

Metal and metal(loids) removal efficiency using genetically engineered microbes: Applications and challenges

The environment is being polluted in different many with metal and metalloid pollution, mostly due to anthropogenic activity, which is directly affecting human and environmental health. Metals and metalloids are highly toxic at low concentrations and contribute primarily to the survival equilibrium of activities in the environment. However, because of non-degradable, they persist in nature and these metal and metalloids bioaccumulate in the food chain. Genetically engineered microorganisms (GEMs) mediated techniques for the removal of metals and metalloids are considered an environmentally safe and economically feasible strategy. Various forms of GEMs, including fungi, algae, and bacteria have been produced by recombinant DNA and RNA technologies, which have been used to eliminate metal and metalloids compounds from the polluted areas. Besides, GEMs have the potentiality to produce enzymes and other metabolites that are capable of tolerating metals stress and detoxify the pollutants. Thus, the aim of this review is to discuss the use of GEMs as advanced tools to produce metabolites, signaling molecules, proteins through genetic expression during metal and metalloids interaction, which help in the breakdown of persistent pollutants in the environment.

Risk analysis of inhaled hexavalent chromium (Cr6+) exposure on blacksmiths from industrial area

Chromium (Cr) is used as a mixture to improve strength and corrosion resistance. Milling and welding processes can expose workers to Cr through dermal exposure and inhalation. Cr exposure can be determined by urine testing. The purpose of this study was to analyze the concentration of Cr in urine (UCr) of workers. This study was carried out using a cross-sectional method. Sampling was conducted in the village of Mekarmaju, Bandung, Indonesia. The number of respondents included 30 blacksmiths, and the control group comprised 10 people who were not blacksmiths. Cr⁶⁺ exposure was measured using a personal sampling pump placed on the collar of the worker's shirt as a breathing zone and then analyzed using a UV-visible spectrophotometer. UCr was measured with a graphite furnace atomic absorption spectrophotometer. The measured Cr⁶⁺ concentration in the exposed working area ranged from 0.03 to 0.63 mg/m³, whereas that in non-exposed area ranged from 0.02 to 0.04 mg/m³. Results showed that 16 out of 30 blacksmiths had a UCr concentration above the biological exposure index (BEI) value, 21 had a higher value than the threshold limit value (TLV), and 22 had hazard index (HI) values > 1, which indicated that Cr has a hazardous potential in the body. The analysis of the exposed and control groups showed a significant difference with a p value of 0.000 for TLV, chronic daily intake, and UCr. These results clearly showed that Cr⁶⁺ exposure may harm the health of these workers in the future. The results obtained in this study can be used to promote workers' awareness on the potential health risk caused by Cr⁶⁺ exposure in the working environment.

Yeast Mycocins: a great potential for application in health

Mycocins have demonstrated inhibition of fungi, bacteria, parasites and viruses, in addition to being studied as epidemiological markers and in the development of vaccines. They are defined as extracellular proteins or glycoproteins with different activities, the main mechanism of action being the inhibition of β-glucan synthesis in the cell wall of sensitive strains. Given the resistance problems created by several microorganisms to agents commonly used in clinical practice, the discovery of new substances with this purpose becomes essential. Mycocins have potential as anti-microbials because they show minimal toxicity and do not present resistance.

Hexavalent Chromate Reductase Activity in Cell Free Extracts of Penicillium sp

A chromium-resistant fungus isolated from contaminated air with industrial vapors can be used for reducing toxic Cr(VI) to Cr(III). This study analyzes in vitro reduction of hexavalent chromium using cell free extract(s) of the fungus that was characterized based on optimal temperature, pH, use of electron donors, metal ions and initial Cr(VI) concentration in the reaction mixture. This showed the highest activity at 37°C and pH 7.0; there is an increase in Cr(VI) reductase activity with addition of NADH as an electron donor, and it was highly inhibited by Hg(2+), Ca(2+) and Mg(2+), and azide, EDTA, and KCN.