We investigated the spatial distribution of heterotrophic bacteria associated with different water masses in the northern East China Sea (ECS) in summer. The surface water masses were divided into the Changjiang Diluted Water (CDW) and high salinity water (HSW). In the CDW region, the concentrations of dissolved inorganic nitrogen (DIN) and chlorophyll-a (Chl-a), and micro Chl-a contribution were high; and bacterial abundance (BA) and ciliate abundance (CA) were also high. In the HSW region with relatively low DIN concentrations, Chl-a concentration and micro Chl-a contribution were low, but pico Chl-a contribution was increased compared to those in the CDW region. BA did not show any significant difference from the CDW region, but CA was decreased. BA showed a positive correlation with Chl-a concentration in the CDW region; however, it did not show a significant correlation with Chl-a concentration in the HSW region. The ratio of bacterial carbon biomass/phytoplankton carbon biomass was exponentially increased with a decrease in the Chl-a concentration. Compared to the past (1990-2000s), the surface phosphate concentrations and the size of dominant phytoplankton have recently decreased in the ECS. Considering this trend of nutrient decrease and miniaturization of the phytoplankton, our results indicate that changes in the strength of the oligotrophic water mass could alter the function of the microbial food web.

This study evaluated the effect of lactic acid bacteria (LAB, a mixture of Enterococcus faecium and Lactobacillus plantarum) supplementation, the storage temperature, and storage period on the fermentation characteristics and in vitro ruminal digestibility of a total mixed ration (TMR). The TMR was prepared into two groups, namely, CON (control TMR without the LAB) and ML (supplementing a mixture of E. faecium and L. plantarum in the ratio of 1% and 2% (v/w), respectively). Both groups were divided and stored at 4°C or 25°C for 3, 7, and 14 d fermentation periods. Supplementing LAB to the TMR did not affect the chemical composition of TMR except for the lactate and acetate concentration. Storage temperatures affected (p<0.05) the chemical composition of the TMR, including pH, lactate, and acetate contents. The chemical composition of TMR was also affected (p<0.05) by the storage period. During in vitro rumen fermentation study, the ML treatment showed lower (p<0.05) dry matter digestibility at 24 h incubation with a higher pH compared to the CON. There was no difference in the in vitro dry matter digestibility (IVDMD) of TMR between the CON and ML treatment however, at 24 h, ML treatment showed lower (p<0.05) IVDMD with a higher pH compared to the CON. The effects of storage temperature and period on IVDMD were not apparent at 24 h incubation. In an in vivo study using Holstein steers, supplementing LAB to the basal TMR for 60 d did not differ in the final body weight and average daily gain. Likewise, the fecal microbiota did not differ between CON and ML. However, the TMR used for the present study did include a commercial yeast in CON, whereas ML did not; therefore, results were, to some extent, compromised in examining the effect of LAB. In conclusion, storage temperature and period significantly affected the TMR quality, increasing acetate and lactate concentration. However, the actual effects of LAB supplementation were equivocal.

To enhance the bioavailability and bioactivities of mixed herbal medicines (RW), they were fermented with lactic-acid bacteria isolated from kimchi into postbiotics (FRW). Then, from the results of the 16s rRNA sequencing analysis, lactic acid bacteria isolated from kimchi were identified to be of two species, namely Lactobacillus sakei and Leuconostoc mesenteroides. The FRW prepared from the RW were extracted using hot water (HW) and 70% EtOH (EtOH) for comparison of their macrophage-stimulating activities. Based on a comparison of the activities of the FRW extracts, nitric oxide (NO) production of HW was significantly higher than that in EtOH. An analysis of the chemical properties of the extracts showed that HW had higher contents of neutral sugar and uronic acid than EtOH as well as contained a large amount of glucose. In addition, crude polysaccharide (CP) was prepared to enhance the macrophage-stimulating activity. The FRW-CP not only secreted immunostimulatory mediators but also increased the expression of immunostimulatory genes (iNOS, TNF-α, MCP-1, and IL-6). The fractionated FRW-CP contained about 90% neutral sugars, and these sugars were mainly composed of glucose, galacturonic acid, and arabinose. Thus, FRW prepared by fermentation of RW with kimchi lactic acid bacteria were found to be immunostimulatory modulators.

This study was carried out to investigate how airborne bacteria are distributed under different temperature conditions while cultivating oyster mushrooms by setting the indoor temperature of the cultivation room to 10°C, 15°C, 20°C, 25°C, and 30°C. The surveys were conducted in April and May, respectively. Airborne bacterial concentrations were distributed in the range of 1.61 × 102 ~ 3.67 × 102 CFU/m3 in April and 5.47 × 102 ~ 7 × 103 CFU/ m3 in May. In May, the indoor air quality maintenance standard (8.0 × 102 CFU/m3) was exceeded in the 10°C, 20°C, and 25°C cultivation rooms. Bacterial concentrations increased significantly in May compared to April. Bacterial concentrations were different between the cultivation rooms at different temperatures. The difference was more pronounced in May than in April. A total of 15 genera and 20 species were isolated from the indoor air of the oyster mushroom cultivation rooms. Overall, it was most abundant in Actinomycetia. Among the species identified, Agrobacterium radiobacter, Brevundimonas vesicularis, Kocuria palustris, K. salsicia, Lysinibacillus fusiformis, and Sphingobacterium siyangense are known to affect human health. This is the first report of airborne bacteria in cultivation rooms at different temperatures used for oyster mushroom cultivation. The results of this study are expected to be used as basic data to understand the indoor environment of thermophilic mushroom cultivation facilities.

음식물류폐기물 직매립, 해양투기 등이 금지됨에 따라 음식물류폐기물은 대부분 자원화를 통해 처리되며 퇴비화하여 생산한 음식물류혼합퇴비(이 하, 음폐퇴비)는 작물 생산성을 향상 등을 위하여 농경지에 퇴비로 사용한다. 하지만, 염분 집적에 의한 작물 생육이 우려되며 이에 따른 피해를 줄이기 위하여 음폐퇴비와 블랙카본, 유용 미생물을 함께 사용하면 염분에 의한 피해를 줄일 수 있을 것으로 기대된다. 이에 본 연구는 음폐퇴비와 바이오차의 한 종류인 블랙카본, 유용 미생물을 처리 시 상추의 수량과 토양 특성 변화를 알아보고자 하였다. 처리구는 무비구(NF), 무기질 비료 (NPK), 무기질 비료 + 음폐퇴비 (NPKF, 대조구), 무기질 비료 + 음폐퇴비 + 블랙 카본 (NPKFC), 무기질 비료 + 음폐퇴비 + 미생물 (NPKFB), 무기질 비료 + 음폐퇴비 + 블랙카본 + 미생물 (NPKFCB)이다. 상추 생육 조사 결과, 생육 후기인 21일째에 NPKFCB 처리구에서 엽장 20.7 cm, 엽폭 20.2 cm, SPAD-502 32.0으로 가장 생육이 좋았으며, 수량 조사 결과 또한 NPKFCB 처리구에서 주당 총 엽수가 28.8개로 가장 많았다. 수량지수는 무처리가 84.1로 가장 낮았고 NPKFCB 처리구에서 128.7로 가장 높았다. 이는 블랙카본에서 공급되는 K, P, Ca 등의 양분과 미생물 활성화가 작물 생산성 향상에 도움을 준 것으로 판단된다. 토양 화학성 분석 결과 pH는 NPKFB 처리구에서 6.9로 가장 높았으며, EC는 NPKF에서 1.7 dS m-1로 가장 높았다.

Grapefruit extract rich in functional substances adjusting pH 5.0 and adding sucrose (final concentration, 2%) was fermented by Leuconostoc mesenteroides CJNU 0147 strain, consequently prepared a fermented grapefruit extract containing dextran. As a result of analyzing the growth inhibitory effect on gut harmful bacterium Clostridium difficile strain using the prepared fermented grapefruit extract, the viable cell count was significantly reduced (p<0.05 vs. control for 0.5 brix as a final concentration; p<0.001 vs. control for 1.0 brix). On the other hand, the proliferative ability of the extract for Bifidobacterium breve strain, which is one of the species of the genus Bifidobacterium well known as human gut beneficial bacteria, was confirmed (p<0.001 vs. control for both 0.5 and 1.0 brix). These results indicate fermented grapefruit extract with Leu. mesenteroides CJNU 0147 strain inhibits the growth of gut harmful bacterium C. difficile and promotes the proliferation of beneficial bacterium B. breve and is expected to be used as a functional food material for gut health.

In this study, probiotic properties such as acid resistance, bile tolerance, intestinal adhesion and fat accumulation inhibition of lactic acid bacteria isolated from kimchi were investigated in order to develop probiotics effective anti-adipogenic effects. Among the 120 types of lactic acid bacteria isolated from kimchi, 42 types of lactic acid bacteria being to acid resistance, 35 types of lactic acid bacteria being to bile resistance, and 24 types of lactic acid bacteria being to both acid resistance and bile resistance were selected. These 24 types were tested for the intestinal adhesion ability which is an essential factor of probiotics’ function and L. rhamnosus GG was used as a positive control in this test. 10 types of lactic acid bacteria having the intestinal adhesion ability were selected. The selected 10 types of lactic acid bacteria were treated in 3T3-L1 cells and intracellular fat was stained with Oil Red O reagent to measure fat accumulation. As a result, in the group treated with lactic acid bacteria OS-15, 48, 102 and 120, fat accumulation was significantly decreased compared with the non-treated group. And the strain OS-48 showed the greatest inhibitory effect on fat accumulation. The lactic acid bacterium OS-48 was identified as Lactiplantibacillus plantarum by analysis based on 16S rRNA sequencing and was named Lactiplantibacillus plantarum OS-48. Therefore, based on the results of this study, L. plantarum OS-48 is expected to be very useful as probiotics with anti-obesity effect in the food industry such as fermented food and functional food.

This study aimed to investigate the effects of antioxidant and anti-inflammatory activities of heat-killed lactic acid bacteria (LAB) produced under different temperature conditions. Regarding probiotic properties, Limosilactobacillus fermentum SMF743 and Lactiplantibacillus plantarum SMF796 isolated from kimchi showed strong acid and bile salt resistance, adhesion activity onto HT-29 cells, and antimicrobial activity against pathogenic bacteria. Based on the results of thermal death time and temperature, heat-killed LAB cells (1 mg/mL) were prepared by heating at 70oC (180 min), 80oC (120 min), 100oC (30 min), and 121oC (15 min). The heat-killed SMF743 and SMF796 showed significantly higher DPPH and ABTS radical scavenging activities than live cells (p<0.05). The heat-killed SMF743 and SMF796 at 70oC or 121oC revealed stronger DPPH and ABTS radical scavenging activities and inhibition of nitric oxide production than those at 80oC or 100oC. Furthermore, heat-killed SMF743 and SMF796 at 121oC significantly reduced the gene expression levels of tumor necrosis factor-, inducible nitric oxide synthase, and cyclooxygenase- 2 up to 53.33%, 58.67%, and 83.67%, respectively, in lipopolysaccharide (LPS)-induced RAW264.7 cells (p<0.05). These results suggest that heat-killed L. fermentum SMF743 and L. plantarum SMF796 can be used as natural antioxidants and anti-inflammatory agents.

Spent nuclear fuel (SNF) is the main source of high-level radioactive wastes (HLWs), which contains approximately 96% of uranium (U). For the safe disposal of the HLWs, the SNF is packed in canisters of cast iron and copper, and then is emplaced within 500 m of host rock surrounded by compacted bentonite clay buffer for at least 100,000 years. However, in case of the failure of the multi-barrier disposal system, U might be migrated through the rock fractures and groundwater, eventually, it could reach to the biosphere. Since the dissolved U interacts with indigenous bacteria under natural and engineered environments over the long storage periods of geologic disposal, it is important to understand the characteristics of U-microbe interactions under the geochemical conditions. In particular, a few of bacteria, i.e., sulfate-reducing bacteria (SRB), are able to reduce soluble U(VI) into insoluble U(IV) under anaerobic conditions by using their metabolisms, resulting in the immobilization of U. In this study, the aqueous U(VI) removal performance and change in bacterial community in response to the indigenous bacteria were investigated to understand the interactions of U-microbe under anaerobic conditions. Three different indigenous bacteria obtained from different depths of granitic groundwater (S1: 44–60 m, S2: 92–116 m, and S3: 234–244 m) were used for the reduction of U(VI)aq. After the anaerobic reaction of 24 weeks, the changes in bacterial community structure in response to the seeding indigenous bacteria were observed by high-throughput 16S rDNA gene sequencing analysis. The highest uranium removal efficiency of 57.8% was obtained in S3 sample, and followed by S2 (43.1%) and S1 (37.7%). Interestingly, SRB capable of reducing U(VI) greatly increased from 4.8% to 44.1% in S3 sample. Among the SRB identified, Thermodesulfovibrio yellowstonii played a key role on the removal of U(VI)aq. Transmission electron microscopy (TEM) analysis showed that the dspacing of precipitates observed in this study was identical with that of uraninite (UO2). This study presents the potential of U(VI)aq removal by indigenous bacteria under deep geological environment.