Microorganisms inhabiting soils contaminated with heavy metals produce melanin,a dark brown pigment,as a survival strategy.In this study,a melanin-producing bacterium,Acinetobacter sp.ME1,with heavy metal tolerance an...Microorganisms inhabiting soils contaminated with heavy metals produce melanin,a dark brown pigment,as a survival strategy.In this study,a melanin-producing bacterium,Acinetobacter sp.ME1,with heavy metal tolerance and plant growth-promoting traits,was isolated from abandoned mine soil.Strain ME1 exhibited growth at concentrations of Zn up to 250 mg/L,Cd and Pb up to 100 mg/L,and Cr up to 50 mg/L.It had the ability to produce the plant hormone indole-3-acetic acid and siderophores along with 1-aminocyclopropane-1-carboxylic acid deaminase and protease activities.Additionally,it showed antioxidant activity,including catalase and 2,2-diphenyl-1-picryhydrazyl(DPPH)scavenging activities.The optimal conditions for melanin production by ME1 were a pH of 7 and a temperature of 35℃.At 1000 mg/L,ME1-extracted melanin exhibited DPPH radical scavenging activity of(25.040±0.007)%,a sun protection factor of 15.200±0.260,and 19.6%antibacterial activity against the plant pathogen Xanthomonas campestris.Furthermore,its adsorption capacity was(0.235±0.073)mg/g melanin for Zn and(0.277±0.008)mg/g melanin for Ni.In plants of Brassica chinensis grown under conditions of hydroponic cultivation with single heavy metal contamination of Cd,Zn,Pb,or Cr,the removal efficiency of each heavy metal was improved by 0.1–1.8 times after 3 d following inoculation with the strain ME1 compared to the plants grown under the same conditions without inoculation.In addition,ME1 inoculation improved the removal efficiency of each heavy metal by 0.1–1.0 times under multiple heavy metal contamination conditions.These findings suggest that Acinetobacter sp.ME1 could be used to enhance phytoremediation efficiency in heavy metal-contaminated soils.Moreover,the melanin it produces also holds promise in cosmetics,household products,and medical applications due to its photoprotective,antioxidant,and antimicrobial properties.展开更多
Volatile organic compounds (VOCs) are harmful to human health and the environment. Recently, loess (Hwangtoh) was used as an eco-friendly interior paint formulation in Korea. It is used even more commonly as a filter ...Volatile organic compounds (VOCs) are harmful to human health and the environment. Recently, loess (Hwangtoh) was used as an eco-friendly interior paint formulation in Korea. It is used even more commonly as a filter carrier to remove VOCs. In this study, we isolated Bacillus strains from a loess filter. The strains that were tolerant to VOCs were labeled according to the series VOC01 to VOC35. Four strains—VOC03, VOC11, VOC18, and VOC30—were investigated for their ability to degrade cyclohexane and toluene. Strain VOC18 best degraded both VOCs, whereas VOC03 demonstrated no ability to degrade VOCs. In keeping with this, VOC18 grew best on cyclohexane or toluene as the sole carbon source. The strains were identified by their physiochemical and phylogenetic characteristics. Strain VOC18 was determined as a strain of Bacillus cereus;VOC11 and VOC30 were determined as differentiated strains of B. thuringiensis. Strain VOC03, which demonstrated high tolerance but no ability to degrade VOCs, was identified as a strain of B. megaterium.展开更多
基金supported by the National Research Foundation of Korea(NRF)grants funded by the Korean government,the Ministry of Science,and the Ministry of Science and Information and Communication Technology(ICT(MSIT))(Nos.2022R1A2C2006615 and RS2023-00217228).
文摘Microorganisms inhabiting soils contaminated with heavy metals produce melanin,a dark brown pigment,as a survival strategy.In this study,a melanin-producing bacterium,Acinetobacter sp.ME1,with heavy metal tolerance and plant growth-promoting traits,was isolated from abandoned mine soil.Strain ME1 exhibited growth at concentrations of Zn up to 250 mg/L,Cd and Pb up to 100 mg/L,and Cr up to 50 mg/L.It had the ability to produce the plant hormone indole-3-acetic acid and siderophores along with 1-aminocyclopropane-1-carboxylic acid deaminase and protease activities.Additionally,it showed antioxidant activity,including catalase and 2,2-diphenyl-1-picryhydrazyl(DPPH)scavenging activities.The optimal conditions for melanin production by ME1 were a pH of 7 and a temperature of 35℃.At 1000 mg/L,ME1-extracted melanin exhibited DPPH radical scavenging activity of(25.040±0.007)%,a sun protection factor of 15.200±0.260,and 19.6%antibacterial activity against the plant pathogen Xanthomonas campestris.Furthermore,its adsorption capacity was(0.235±0.073)mg/g melanin for Zn and(0.277±0.008)mg/g melanin for Ni.In plants of Brassica chinensis grown under conditions of hydroponic cultivation with single heavy metal contamination of Cd,Zn,Pb,or Cr,the removal efficiency of each heavy metal was improved by 0.1–1.8 times after 3 d following inoculation with the strain ME1 compared to the plants grown under the same conditions without inoculation.In addition,ME1 inoculation improved the removal efficiency of each heavy metal by 0.1–1.0 times under multiple heavy metal contamination conditions.These findings suggest that Acinetobacter sp.ME1 could be used to enhance phytoremediation efficiency in heavy metal-contaminated soils.Moreover,the melanin it produces also holds promise in cosmetics,household products,and medical applications due to its photoprotective,antioxidant,and antimicrobial properties.
文摘Volatile organic compounds (VOCs) are harmful to human health and the environment. Recently, loess (Hwangtoh) was used as an eco-friendly interior paint formulation in Korea. It is used even more commonly as a filter carrier to remove VOCs. In this study, we isolated Bacillus strains from a loess filter. The strains that were tolerant to VOCs were labeled according to the series VOC01 to VOC35. Four strains—VOC03, VOC11, VOC18, and VOC30—were investigated for their ability to degrade cyclohexane and toluene. Strain VOC18 best degraded both VOCs, whereas VOC03 demonstrated no ability to degrade VOCs. In keeping with this, VOC18 grew best on cyclohexane or toluene as the sole carbon source. The strains were identified by their physiochemical and phylogenetic characteristics. Strain VOC18 was determined as a strain of Bacillus cereus;VOC11 and VOC30 were determined as differentiated strains of B. thuringiensis. Strain VOC03, which demonstrated high tolerance but no ability to degrade VOCs, was identified as a strain of B. megaterium.
