Journal of Microbiology

Journal Articles

Biosynthesis of adipic acid in metabolically engineered Saccharomyces cerevisiae: Xi Zhang , Yingli Liu , Jing Wang , Yunying Zhao , Yu Deng; J. Microbiol. 2020;58(12):1065-1075. Published online October 23, 2020; DOI: https://doi.org/10.1007/s12275-020-0261-7

16 View
0 Download
13 Citations

Abstract: Adipic Acid (AA) is a valued platform chemical compound, which can be used as a precursor of nylon-6,6. Due to the generation of an enormous amount of nitric oxide metabolites and the growing depletion of oil resources as a result of AA production from a mixture of cyclohexanol and cyclohexanone, the microbial methods for synthesizing AA have attracted significant attention. Of the several AA-producing pathways, the reverse adipate degradation pathway in Thermobifida fusca (Tfu RADP) is reported to be the most efficient, which has been confirmed in Escherichia coli. In this study, the heterologous Tfu RADP was constructed for producing AA in S. cerevisiae by co-expressing genes of Tfu_ 0875, Tfu_2399, Tfu_0067, Tfu_1647, Tfu_2576, and Tfu_ 2576. The AA titer combined with biomass, cofactors and other by-products was all determined after fermentation. During batch fermentation in a shake flask, the maximum AA titer was 3.83 mg/L, while the titer increased to 10.09 mg/L during fed-batch fermentation in a 5-L bioreactor after fermentation modification.

Exploring the antibiotic resistome in activated sludge and anaerobic digestion sludge in an urban wastewater treatment plant via metagenomic analysis: Keunje Yoo , Hyunji Yoo , Jangho Lee , Eun Joo Choi , Joonhong Park; J. Microbiol. 2020;58(2):123-130. Published online December 23, 2019; DOI: https://doi.org/10.1007/s12275-020-9309-y

12 View
0 Download
49 Citations

Abstract: Antibiotic resistance genes (ARGs) are emerging contaminants that pose a potential threat to human health worldwide. Urban wastewater treatment plants (WWTPs) are a main source of both antibiotic-resistant bacteria and ARGs released into the environment. Nevertheless, the propagation of ARGs and their underlying mechanisms and the dynamics of mobile genetic elements (MGEs) in WWTPs have rarely been investigated in South Korea. In this study, shotgun metagenomic analysis was used to identify comprehensive ARGs and their mechanisms, bacterial communities, and MGEs from 4 configurations with 2 activated sludge (AS) and 2 anaerobic digestion sludge (ADS) samples. A total of 181 ARG subtypes belonging to 22 ARG types were broadly detected, and the ARG abundances in the AS samples were 1.3–2.0 orders of magnitude higher than in the ADS samples. Multidrug and bacitracin resistance genes were the predominant ARG types in AS samples, followed by ARGs against sulfonamide, tetracycline, and β-lactam. However, the composition of ARG types in ADS samples was significantly changed. The abundance of multidrug and β-lactam resistance genes was drastically reduced in the ADS samples. The resistance genes of MLS were the predominant, followed by ARGs against sulfonamide and tetracycline in the ADS samples. In addition, plasmids were the dominant MGEs in the AS samples, while integrons (intI1) were the dominant MGEs in the ADS samples. These results provide valuable information regarding the prevalence of ARG types and MGEs and the difference patterns between the AS and ADS systems.

Metagenomic analysis reveals the prevalence and persistence of antibiotic- and heavy metal-resistance genes in wastewater treatment plant: Sachin Kumar Gupta , Hanseob Shin , Dukki Han , Hor-Gil Hur , Tatsuya Unno; J. Microbiol. 2018;56(6):408-415. Published online June 1, 2018; DOI: https://doi.org/10.1007/s12275-018-8195-z

11 View
0 Download
72 Citations

Abstract: The increased antibiotic resistance among microorganisms has resulted into growing interest for investigating the wastewater treatment plants (WWTPs) as they are reported to be the major source in the dissemination of antibiotic resistance genes (ARGs) and heavy metal resistance genes (HMRGs) in the environment. In this study, we investigated the prevalence and persistence of ARGs and HMRGs as well as bacterial diversity and mobile genetic elements (MGEs) in influent and effluent at the WWTP in Gwangju, South Korea, using high-throughput sequencing based metagenomic approach. A good number of broad-spectrum of resistance genes (both ARG and HMRG) were prevalent and likely persistent, although large portion of them were successfully removed at the wastewater treatment process. The relative abundance of ARGs and MGEs was higher in effluent as compared to that of influent. Our results suggest that the resistance genes with high abundance and bacteria harbouring ARGs and MGEs are likely to persist more through the treatment process. On analyzing the microbial community, the phylum Proteobacteria, especially potentially pathogenic species belonging to the genus Acinetobacter, dominated in WWTP. Overall, our study demonstrates that many ARGs and HMRGs may persist the treatment processes in WWTPs and their association to MGEs may contribute to the dissemination of resistance genes among microorganisms in the environment.

Comparative Study of Olive Oil Mill Wastewater Treatment Using Free and Immobilized Coriolopsis polyzona and Pycnoporus coccineus: Mohamed Neifar , Atef Jaouani , María Jesús Martínez , Michel J. Penninckx; J. Microbiol. 2012;50(5):746-753. Published online November 4, 2012; DOI: https://doi.org/10.1007/s12275-012-2079-4

12 View
0 Download
9 Citations

Abstract: The efficiency of the two white-rot fungi Pycnoporus coccineus and Coriolopsis polyzona in the Olive Oil Mill Wastewater (OOMW) treatment was investigated. Both fungi were active in the decolourisation and COD removal of OOMW at 50 g/L COD, but only the first fungus remains effective on the crude effluent (COD=100 g/L). Moreover P. coccineus was less affected by oxygen supplementation and exhibited a high tolerance to agitation in comparison to C. polyzona. However, it required a nitrogen supplementation to obtain faster and higher COD removal. To overcome the negative effect of agitation on fungi growth and efficiency, immobilisation of C. polyzona and P. coccineus in polyurethane foam was applied. The immobilized system showed better COD decreases during three consecutive batches without remarkable loss of performances. The results obtained in this study suggested that immobilized C. polyzona and especially immobilized P. coccineus might be applicable to a large scale for the removal colour and COD of OOMW.

Research Support, Non-U.S. Gov'ts

Effect of Natural Mediators on the Stability of Trametes trogii Laccase during the Decolourization of Textile Wastewaters: Rim Khlifi-Slama , Tahar Mechichi , Sami Sayadi , Abdelhafidh Dhouib; J. Microbiol. 2012;50(2):226-234. Published online April 27, 2012; DOI: https://doi.org/10.1007/s12275-012-1421-1

14 View
0 Download
26 Citations

Abstract: The purpose of the present study was to determine the effect of natural mediators on the stability of the Trametes trogii crude laccase in the process of decolourization of textile effluents. Acetosyringone allowed the highest wastewaters decolourization rate of 25%. At higher concentrations of acetosyringone, the relative activity of laccase decreased approximately by between 38% and 88% after 5 days of incubation. T. trogii laccase was strongly inactivated at 3 mM syringaldehyde, after 3 days of incubation. However, laccase activity is more stable in the presence of the vanillin and m-coumarate. The T. trogii growth on solid effluentbased- medium was examined and evaluated by measuring the colony diameter in cm. T. trogii was completely inhibited on 100:0 and 80:20 effluent:water solid medium, however, colony diameter reached 5 cm on 60:40 effluent:water solid medium after 13–14 days incubation. When the textile effluent was pre-treated with laccase and laccase-acetosyringone system, the colony diameter of 2 cm of T. trogii on 80:20 effluent:water solid medium was reached after 14 and 10 days of incubation respectively.

Dominance of Endospore-forming Bacteria on a Rotating Activated Bacillus Contactor Biofilm for Advanced Wastewater Treatment: Seong Joo Park , Jerng Chang Yoon , Kwang-Soo Shin , Eung Ho Kim , Soobin Yim , Yeon-Je Cho , Gi Moon Sung , Dong-Geun Lee , Seung Bum Kim , Dong-Uk Lee , Sung-Hoon Woo , Ben Koopman; J. Microbiol. 2007;45(2):113-121.; DOI: https://doi.org/2525 [pii]

11 View
0 Download

Abstract: The bacterial diversity inherent to the biofilm community structure of a modified rotating biological contactor wastewater treatment process, referred to as the Rotating Activated Bacillus Contactor (RABC) process, was characterized in this study, via both culture-dependent and culture-independent methods. On the basis of culture-dependent methods, Bacillus sp. were found to exist in large numbers on the biofilm (6.5% of the heterotrophic bacteria) and the microbial composition of the biofilms was quite simple. Only three phyla were identified-namely, the Proteobacteria, the Actinobacteria (High G+C Gram-positive bacteria), and the Firmicutes (Low G+C Gram-positive bacteria). The culture-independent partial 16S rDNA sequence analysis revealed a considerably more diverse microbial composition within the biofilms. A total of eight phyla were recovered in this case, three of which were major groups: the Firmicutes (43.9%), the Proteobacteria (28.6%), and the Bacteroidetes (17.6%). The remaining five phyla were minor groups: the Planctomycetes (4.4%), the Chlorobi (2.2%), the Actinobacteria (1.1%), the Nitrospirae (1.1%), and the Verrucomicrobia (1.1%). The two most abundant genera detected were the endospore-forming bacteria (31.8%), Clostridium and Bacillus, both of which are members of the Firmicutes phylum. This finding indicates that these endospore-forming bacteria successfully colonized and dominated the RABC process biofilms. Many of the colonies or clones recovered from the biofilms evidenced significantly high homology in the 16S rDNA sequences of bacteria stored in databases associated with advanced wastewater treatment capabilities, including nitrification and denitrification, phosphorus accumulation, the removal of volatile odors, and the removal of chlorohydrocarbons or heavy metals. The microbial community structures observed in the biofilms were found to correlate nicely with the enhanced performance of advanced wastewater treatment protocols.

Journal Article

The Role of Enzymes Produced by White-Rot Fungus Irpex lacteus in the Decolorization of the Textile Industry Effluent: Kwang-Soo Shin; J. Microbiol. 2004;42(1):37-41.; DOI: https://doi.org/2003 [pii]

14 View
0 Download

Abstract: The textile industry wastewater has been decolorized efficiently by the white rot fungus, Irpex lacteus, without adding any chemicals. The degree of the decolorization of the dye effluent by shaking or stationary cultures is 59 and 93%, respectively, on the 8th day. The higher level of manganese-dependent peroxidase (MnP) and non-specific peroxidase (NsP) was detected in stationary cultures than in the cultures shaken. Laccase activities were equivalent in both cultures and its level was not affected significantly by the culture duration. Neither lignin peroxidase (LiP) nor Remazol Brilliant Blue R oxidase (RBBR ox) was detected in both cultures. The absorbance of the dye effluent was significantly decreased by the stationary culture filtrate of 7 days in the absence of Mn (II) and veratryl alcohol. In the stationary culture filtrate, three or more additional peroxidase bands were detected by the zymogram analysis.

Research Support, Non-U.S. Gov't

Arthrobacter soli sp. nov., a Novel Bacterium Isolated from Wastewater Reservoir Sediment: Seong Woon Roh , Youlboong Sung , Young-Do Nam , Ho-Won Chang , Kyoung-Ho Kim , Jung-Hoon Yoon , Che Ok Jeon , Hee-Mock Oh , Jin-Woo Bae; J. Microbiol. 2008;46(1):40-44.; DOI: https://doi.org/10.1007/s12275-007-0239-8

13 View
0 Download
73 Citations

Abstract: A novel Gram-positive bacterium, designated SYB2T, was isolated from wastewater reservoir sediment, and a polyphasic taxonomic study was conducted based on its morphological, physiological, and biochemical features, as well as the analysis of its 16S rRNA gene sequence. During the phylogenetic analysis of the strain SYB2T, results of a 16S rRNA gene sequence analysis placed this bacterium in the genus Arthrobacter within the family Micrococcaceae. SYB2T and Arthrobacter protophormiae ATCC 19271T, the most closely related species, both exhibited a 16S rRNA gene sequence similarity of 98.99%. The genomic DNA G+C content of the novel strain was found to be 62.0 mol%. The predominant fatty acid composition was anteiso-C15:0, anteiso-C17:0, iso-C16:0, and iso-C15:0. Analysis of 16S rRNA gene sequences and DNA-DNA relatedness, as well as physiological and biochemical tests, showed genotypic and phenotypic differences between strain SYB2T and other Arthrobacter species. The type strain of the novel species was identified as SYB2T (= KCTC 19291T= DSM 19449T).

First
Prev
Page of 1
Next
Last

Search