Bioprocess of Kosa bioaerosols: effect of ultraviolet radiation on airborne bacteria within Kosa (Asian dust).

Kosa (Asian dust) is a well-known weather phenomenon in which aerosols are carried by the westerly winds from inland China to East Asia. Recently, the frequency of this phenomenon and the extent of damage caused have been increasing. The airborne bacteria within Kosa are called Kosa bioaerosols. Kosa bioaerosols have affected ecosystems, human health and agricultural productivity in downwind areas. In order to develop a new and useful bacterial source and to identify the source region of Kosa bioaerosols, sampling, isolation, identification, measurement of ultraviolet (UV) radiation tolerance and experimental simulation of UV radiation conditions were performed during Kosa bioaerosol transportation. We sampled these bioaerosols using a Cessna 404 airplane and a bioaerosol sampler at an altitude of approximately 2900 m over the Noto Peninsula on March 27, 2010. The bioaerosol particles were isolated and identified as Bacillus sp. BASZHR 1001. The results of the UV irradiation experiment showed that the UV radiation tolerance of Kosa bioaerosol bacteria was very high compared with that of a soil bacterium. Moreover, the UV radiation tolerance of Kosa bioaerosol spores was higher than that of soil bacterial spores. This suggested that Kosa bioaerosols are transported across the atmosphere as living spores. Similarly, by the experimental simulation of UV radiation conditions, the limited source region of this Kosa bioaerosol was found to be southern Russia and there was a possibility of transport from the Kosa source area.

Function of rayon fibers with metallophthalocyanine derivatives: potential of low-molecular weight polycyclic aromatic hydrocarbon removal and Bacillus sp. removal.

Polycyclic aromatic hydrocarbons (PAHs) are known as carcinogenic and/or mutagenic substances, and are present at high concentration in polluted environments. It has recently been reported that spore-forming bacteria (e.g., Bacillus spp.) can be transported long distances alive in the atmosphere, which raises the possibility that some of the transported bacteria could have adverse effects on human health. There is thus a need for filters that can remove gaseous PAHs from the air that people breathe and that can inhibit bacterial growth on the filters. We focused on metallophthalocyanine derivatives (M-Pc) which are known to adsorb PAHs as well as to inhibit the growth of bacteria as a potential filtering agent. In this study, we developed different types of M-Pc-supported rayon fibers by changing central metals, functional groups, concentrations of M-Pc and rayon types, and evaluated their removal effects by measuring adsorption rates of 3- and 4-ring PAHs with a HPLC and growth curves of Bacillus sp. with a spectrophotometer. The results showed that both the effects depended on functional groups and concentrations of M-Pc, and rayon types. The most effective combination was observed in Fe-Pc with sulfo group supported on cationized rayon fiber at the concentration of 2 to 3.3 wt%. Central metal species of M-Pc were influenced only on the antibacterial properties. This fiber would be applicable to filtering agents and textiles.

Origin of non-spherical particles in the boundary layer over Beijing, China: based on balloon-borne observations.

Vertical structures of aerosols from the ground to about 1,000 m altitude in Beijing were measured with a balloon-borne optical particle counter. The results showed that, in hazy days, there were inversions at approximately 500-600 m, below which the particulate matters were well mixed vertically, while the concentration of particles decreased sharply above the mixing layer. Electron microscopic observation of the particles collected with the balloon-borne impactor indicates that the composition of particles is different according to weather conditions in the boundary mixing layer of Beijing city and suggests that dust particles are always dominant in coarse-mode particles. Interestingly, sea-salt particles are frequently identified, suggesting the importance of marine air inflow to the Beijing area even in summer. The Ca-rich spherical particles are also frequently identified, suggesting chemical modification of dust particle by NOx or emission of CaO and others from local emission. Additionally, those types of particles showed higher concentration above the mixing layer under the relatively calm weather condition of summer, suggesting the importance of local-scale convection found in summer which rapidly transported anthropogenic particles above the mixing layer. Lidar extinction profiles qualitatively have good consistency with the balloon-borne measurements. Attenuation effects of laser pulse intensity are frequently observed due to high concentration of particulate matter in the Beijing atmosphere, and therefore quantitative agreement of lidar return and aerosol concentration can be hardly observed during dusty condition. Comparing the depolarization ratio obtained from the lidar measurements with the balloon-borne measurements, the contribution of the dry sea-salt particles, in addition to the dust particles, is suggested as an important factor causing depolarization ratio in the Beijing atmosphere.

Variations in the structure of airborne bacterial communities in a downwind area during an Asian dust (Kosa) event.

Asian dust (Kosa) events transport airborne microorganisms that significantly impact biological ecosystems, human health, and ice-cloud formation in downwind areas. However, the composition and population dynamics of airborne bacteria have rarely been investigated in downwind areas during Kosa events. In this study, air samplings were sequentially performed at the top of a 10-m high building within the Kosa event arrival area (Kanazawa City, Japan) from May 1 to May 7, 2011, during a Kosa event. The particle concentrations of bacterial cells and mineral particles were ten-fold higher during the Kosa event than on non-Kosa event days. A 16S ribosomal DNA clone library prepared from the air samples primarily contained sequences from three phyla: Cyanobacteria, Firmicutes, and Alphaproteobacteria. The clones from Cyanobacteria were mainly from a marine type of Synechococcus species that was dominant during the first phase of the Kosa event and was continuously detected throughout the Kosa event. The clones from Alphaproteobacteria were mainly detected at the initial and final periods of the Kosa event, and phylogenetic analysis showed that their sequences clustered with those from a marine bacterial clade (the SAR clade) and Sphingomonas spp. During the middle of the Kosa event, the Firmicutes species Bacillus subtilis and Bacillus pumilus were predominant; these species are known to be predominant in the atmosphere above the Chinese desert, which is the source of the dust during Kosa events. The clones obtained after the Kosa event had finished were mainly from Bacillus megaterium, which is thought to originate from local terrestrial areas. Our results suggest that airborne bacterial communities at the ground level in areas affected by Kosa events change their species compositions during a Kosa event toward those containing terrestrial and pelagic bacteria transported from the Sea of Japan and the continental area of China by the Kosa event.

Asian dust particles converted into aqueous droplets under remote marine atmospheric conditions.

The chemical history of dust particles in the atmosphere is crucial for assessing their impact on both the Earth's climate and ecosystem. So far, a number of studies have shown that, in the vicinity of strong anthropogenic emission sources, Ca-rich dust particles can be converted into aqueous droplets mainly by the reaction with gaseous HNO(3) to form Ca(NO(3))(2). Here we show that other similar processes have the potential to be activated under typical remote marine atmospheric conditions. Based on field measurements at several sites in East Asia and thermodynamic predictions, we examined the possibility for the formation of two highly soluble calcium salts, Ca(NO(3))(2) and CaCl(2), which can deliquesce at low relative humidity. According to the results, the conversion of insoluble CaCO(3) to Ca(NO(3))(2) tends to be dominated over urban and industrialized areas of the Asian continent, where the concentrations of HNO(3) exceed those of HCl ([HNO(3)/HCl] >  âˆ¼ 1). In this regime, CaCl(2) is hardly detected from dust particles. However, the generation of CaCl(2) becomes detectable around the Japan Islands, where the concentrations of HCl are much higher than those of HNO(3) ([HNO(3)/HCl] <  âˆ¼ 0.3). We suggest that elevated concentrations of HCl in the remote marine boundary layer are sufficient to modify Ca-rich particles in dust storms and can play a more important role in forming a deliquescent layer on the particle surfaces as they are transported toward remote ocean regions.

Phylogenetic analysis of atmospheric halotolerant bacterial communities at high altitude in an Asian dust (KOSA) arrival region, Suzu City.

The microbial communities transported by Asian desert dust (KOSA) events have attracted much attention as bioaerosols because the transported microorganisms are thought to influence the downwind ecosystems in Korea and Japan. However, the atmospheric microbial community has not been investigated at high altitude in the KOSA arrival area. In this study, to estimate the viability and diversity of atmospheric halotolerant bacteria, which are expected to resist to various environmental stresses as well as high salinities, bioaerosol samples were collected at 10 and 600 m above the ground within the KOSA arrival area, Suzu City, Japan, during KOSA events. During the sampling period, the particle numbers at 600 m were higher than those at 10 m, suggesting that large particles of aerosol fall from the high altitude of 600 m to the ground surface. The microorganisms in bioaerosol samples grew in media containing up to 15% NaCl concentrations demonstrating the viability of the halotolerant bacteria in bioaerosol samples. The PCR-DGGE analysis using 16S rDNA revealed that the bacterial species in NaCl-amended cultures were similar to the bacteria detected from the genomic DNA directly extracted from the bioaerosol samples. The 16S rDNA sequences of bacterial communities in bioaerosol samples were classified into 4 phylotypes belonging to the Bacilluscereus or Bacillussubtilis group. The bioaerosol samples collected at 600 m included 2 phylotypes belonging to B. subtilis, and one phylotype among all 4 phylotypes was identical between the samples at 10 and 600 m. In the atmosphere at 600 m, the halotolerant bacterial community was expected to remain viable, and the species composition was expected to include a few species of the genus Bacillus. During this investigation period, these atmospheric bacteria may have been vertically transported to the ground surface, where the long-range KOSA particle transport from China is frequently observed.

Immobilization of cross-linked lipase aggregates onto magnetic beads for enzymatic degradation of polycaprolactone.

Candida rugosa lipase was immobilized on amino-functionalized magnetic supports via cross-linked enzyme aggregates (CLEA) and used to enhance the enzymatic degradation of polycaprolactone (PCL). The maximum amounts of lipase immobilized on the magnetic beads using glutaraldehyde as a coupling agent were determined to be 33.7 mg/g of beads with an 81% recovery of activity after immobilization. Compared to the free enzyme, the immobilized lipase showed the optimum pH at 1 unit higher (pH 8.0) and also retained its enzymatic activity at higher temperatures. There was 62.9% retention of lipase activity after 30 consecutive reuses, indicating its stability and reusability in aqueous media. Moreover, the immobilized lipase maintained more than 80% of its initial activity during 30 days storage period, while the free lipase lost all under same condition. In addition, the immobilized lipase showed a more than 6-fold increase in biodegradability over the free lipase when the immobilized lipase was used to degrade PCL in a batch system. Higher thermal and storage stability, as well as good durability after repeated use of the immobilized lipase CLEA, highlights its potential applicability as large scale continuous systems for the enzymatic degradation of PCL.

Biodegradation of diisodecyl phthalate (DIDP) by Bacillus sp. SB-007.

In this study, diisodecyl phthalate (DIDP) was efficiently degraded by Bacillus sp. SB-007. The optimal conditions for DIDP (100 mg l(-1)) degradation by Bacillus sp. SB-007 in a mineral salts medium were found to be pH 7.0 at 30 degrees C, stirring at 200 rpm. The specific rate of DIDP degradation was found to be concentration dependent with a maximum of 4.87 mg DIDP l(-1) h(-1). DIDP was transformed rapidly by Bacillus sp. SB-007 with the formation of monoisodecyl phthalate and phthalic acid, which subsequently degraded further. These results highlight the potential of this bacterium for removing DIDP contaminated waste in the environment.

LIDAR measurements of the vertical aerosol profile and optical depth during the ACE-Asia 2001 IOP, at Gosan, Jeju Island, Korea.

In order to investigate the characteristic of optical properties of Asian dust particles, the atmospheric aerosol vertical profile was measured with the multi-wavelength LIDAR system, at the Gosan super site (33 degrees 17'N, 126 degrees 10'E) in Jeju Island, Korea, during the ACE-Asia intensive observation period, 11 March-4 May 2001. An air mass backward trajectory analysis, using Hysplit-4, was carried out to track the aerosol plume, with high mass loading, from the Chinese desert regions during the period of Asian dust storm events. Vertical atmospheric aerosol profiles on three major Asian dust storm event days, 22 March and 13 and 26 April 2001, have been analyzed. The LIDAR-derived aerosol optical depth values were compared with those measured by a collocated sunphotometer.