TY - JOUR
T1 - Dominance of gas-eating, biofilm-forming Methylobacterium species in the evaporator cores of automobile air-conditioning systems
AU - Park, Chulwoo
AU - Jung, Hye Su
AU - Park, Soyoon
AU - Jeon, Che Ok
AU - Park, Woojun
N1 - Funding Information:
This work was supported by the Hyundai Motor Company and a National Research Foundation of Korea (NRF) grant awarded by the Korean government (MSIP) (grant NRF-2019R1A2C1088452). We thank Hyo Jung Eom for providing CLSM image data to our laboratory. We also thank the Hyundai Motor Company for providing raw data of the microbial community on ECs from ACS and on VOC profiles from Korean cities.
Publisher Copyright:
© 2020 Park et al.
PY - 2020/1/1
Y1 - 2020/1/1
N2 - Microbial communities in the evaporator core (EC) of automobile airconditioning systems have a large impact on indoor air quality, such as malodor and allergenicity. DNA-based microbial population analysis of the ECs collected from South Korea, China, the United States, India, and the United Arab Emirates revealed the extraordinary dominance of Methylobacterium species in EC biofilms. Mixedvolatile organic compound (VOC) utilization and biofilm-forming capabilities were evaluated to explain the dominance of Methylobacterium species in the ECs. The superior growth of all Methylobacterium species could be possible under mixed-VOC conditions. Interestingly, two lifestyle groups of Methylobacterium species could be categorized as the aggregator group, which sticks together but forms a small amount of biofilm, and the biofilm-forming group, which forms a large amount of biofilm, and their genomes along with phenotypic assays were analyzed. Pili are some of the major contributors to the aggregator lifestyle, and succinoglycan exopolysaccharide production may be responsible for the biofilm formation. However, the coexistence of these two lifestyle Methylobacterium groups enhanced their biofilm formation compared to that with each single culture. IMPORTANCE Air-conditioning systems (ACS) are indispensable for human daily life; however, microbial community analysis in automobile ACS has yet to be comprehensively investigated. A bacterial community analysis of 24 heat exchanger fins from five countries (South Korea, China, the United States, India, and the United Arab Emirates [UAE]) revealed that Methylobacterium species are some of the dominant bacteria in automobile ACS. Furthermore, we suggested that the predominance of Methylobacterium species in automobile ACS is due to the utilization of mixed volatile organic compounds and their great ability for aggregation and biofilm formation.
AB - Microbial communities in the evaporator core (EC) of automobile airconditioning systems have a large impact on indoor air quality, such as malodor and allergenicity. DNA-based microbial population analysis of the ECs collected from South Korea, China, the United States, India, and the United Arab Emirates revealed the extraordinary dominance of Methylobacterium species in EC biofilms. Mixedvolatile organic compound (VOC) utilization and biofilm-forming capabilities were evaluated to explain the dominance of Methylobacterium species in the ECs. The superior growth of all Methylobacterium species could be possible under mixed-VOC conditions. Interestingly, two lifestyle groups of Methylobacterium species could be categorized as the aggregator group, which sticks together but forms a small amount of biofilm, and the biofilm-forming group, which forms a large amount of biofilm, and their genomes along with phenotypic assays were analyzed. Pili are some of the major contributors to the aggregator lifestyle, and succinoglycan exopolysaccharide production may be responsible for the biofilm formation. However, the coexistence of these two lifestyle Methylobacterium groups enhanced their biofilm formation compared to that with each single culture. IMPORTANCE Air-conditioning systems (ACS) are indispensable for human daily life; however, microbial community analysis in automobile ACS has yet to be comprehensively investigated. A bacterial community analysis of 24 heat exchanger fins from five countries (South Korea, China, the United States, India, and the United Arab Emirates [UAE]) revealed that Methylobacterium species are some of the dominant bacteria in automobile ACS. Furthermore, we suggested that the predominance of Methylobacterium species in automobile ACS is due to the utilization of mixed volatile organic compounds and their great ability for aggregation and biofilm formation.
KW - Aggregation
KW - Air-conditioning systems
KW - Biofilm
KW - Genomes
KW - Methylobacterium
KW - Volatile organic compounds
UR - http://www.scopus.com/inward/record.url?scp=85077941331&partnerID=8YFLogxK
U2 - 10.1128/mSphere.0761-19
DO - 10.1128/mSphere.0761-19
M3 - Article
C2 - 31941811
AN - SCOPUS:85077941331
VL - 5
JO - mSphere
JF - mSphere
SN - 2379-5042
IS - 1
M1 - e00761
ER -