Microbial Ecosystem in Sunderban Mangrove Forest Sediment,North-East Coast of Bay of Bengal,India

This is the first documentation of seasonal and spatial fluctuation of the culturable microbial population collected from different zones in the sediment of the Sunderban mangrove forest. The population of cellulose degrading bacteria, [mean value of CFU 6.189 ± 1.025 × 10⁶ (g dry weight of sediment)^?1] was found to be maximum during post monsoon in the deep forest region, whereas, the fungal population [mean value of CFU 3.424 ± 0.886 × 10⁶ (g dry weight of sediment)^?1] was found to be maximum during pre-monsoon in the rooted region. The abundances of microbes, in decreasing order, studied from different zones are nitrifying bacteria [mean value of CFU 1.125 ± 0.359 × 10⁶ (g dry weight of sediment)^?1], phosphorous solubilizing bacteria (PSB) [mean value of CFU 0.805 ± 0.322 × 10⁶ (g dry weight of sediment)^?1], free living nitrogen fixing bacteria [mean value of CFU 0.417 ± 0.120 × 10⁶ (g dry weight of sediment)^?1] and sulfur reducing bacteria (SRB) [mean value of CFU 0.356 ± 0.125 × 10⁶ (g dry weight of sediment)^?1]. The content of organic carbon in the soil decreased from the deep forest region to the rooted and unrooted region but a reverse profile was found for soil salinity and soil silicate concentration. The results from the present study indicate that the monsoon cycle has a pronounced effect on the microbially dominated biogeochemistry in the sediment and consequently on the ecology of the Sundarban mangrove forest.     

Application of immobilized tannase from <Emphasis Type="Italic">Aspergillus niger</Emphasis> for the removal of tannin from myrobalan juice

Microbial diversity of soil and water samples collected from pyrochemicals exposed areas of Virdhunagar district (Tamil Nadu, India) was studied. Soil and water samples from cultivable area, waste land and city area of the same region were also studied for a comparative acount. There is a remarkable reduction in total heterotrophic bacterial population (THB) in pyrochemicals exposed soil and water samples (42 × 10⁴ CFU/g and 5.6 × 10⁴ CFU/ml respectively), compared to the THB of cultivable area soil and water samples (98 × 10⁷ CFU/g and 38.6 × 10⁷ CFU/ml). The generic composition the THB of the pyrochemicals exposed samples too exhibited considerable change compared to other samples. Pseudomonas sp. was the predominant one (41.6%) followed by Achromobacter sp. (25%) in pyrochemical exposed soil and Pseudomonas sp. was the predominant one (25%) in pyrochemical exposed water samples followed by Bacillus sp. (25%) and Micrococcus sp. (16.6%). It was observed that Cornybacterium sp. and Micrococcus sp. were absent completely in pyrochemical exposed soil and Achromobacter sp. was missing in the pyrochemical exposed water samples, which were present in the other samples. The outcome of this study clearly demonstrates that pollutants such as chemicals used in pyrotechniques affect the microbial biodiversity and suitable measures have to be taken to control the pollution level and to save biodiversity.     

Microbial population,stability and maturity analysis of rotary drum composting of water hyacinth

Water hyacinth is a noxious aquatic weed growing over a wide variety of wetland. One of the effective methods of its treatment is rotary drum composting. Hence, microbial succession in the rotary drum composting of water hyacinth was studied along with stability and maturity. Different ratios of water hyacinth, cow dung and sawdust, i.e. 8: 1: 1, 7: 2: 1, 6: 3: 1, 5: 4: 1 and 10: 0: 0 (control), respectively, were taken. A total weight of 150 kg was maintained. Maximum degradation was observed in the trial 3 (6: 3: 1), which showed maximum temperature rise up to 56.5°C. The total mesophilic bacterial count changed from 4.73 × 10¹² to 2.5 × 10⁷ colony forming unit (CFU)/g compost during the composting period. Spore forming population reached the highest count of 3.3 × 10¹⁰ CFU/g in the thermophilic phase of composting. Actinomycetes, streptomycetes and fungi counts decreased to about 2.4 × 10⁷ CFU/g, 6.5×10⁵ CFU/g and 6.79 × 10⁵ CFU/g, respectively, at the end of composting period. A maximum reduction of 78.7% in oxygen uptake rate and 90.6% in CO₂ evolution rate was observed. This showed the highest stability of the compost sample. But the maximum volatile solids reduction of 45.9% signified the high content of recalcitrant lignocellulosic material. Indicator organisms were reduced to acceptable standards of sanitation.     

Effect of different salinities of a dynamic water system on biofilm formation

AISI-1020 carbon steel coupons were fixed onto a water circulation loop in order to study the effect of varying NaCl concentrations on formation of biofilms by natural populations of microorganisms. Overall, we observed a reduction in the number of bacteria attached to the metal surfaces as NaCl levels increased. At 12.85 and 80 g/l NaCl, the respective bacterial counts were: 1.7×10⁹ CFU/cm² and 7.5×10² CFU/cm² for aerobic species; 1.3×10⁴ CFU/cm² and 2.1×10 CFU/cm² for anaerobic species; and 1.8×10³ CFU/cm² and 4.6×10 CFU/cm² for sulfate-reducing species. However, the opposite trend was observed for the numbers of iron-reducing bacteria: 4.1×10⁶ CFU/cm² at 12.85 g/l NaCl and 7.5 10⁸ CFU/cm² at 80 g/l NaCl, respectively. Fungal counts remained constant throughout the experimental period. The salt concentration at which the maximum corrosion rate was observed was 35 g/l. In view of the marked loss of metal mass recorded at this salinity, AISI-1020 carbon steel proved to belong to the group of alloys less resistant to corrosion. Journal of Industrial Microbiology & Biotechnology (2000) 25, 45–48. Received 07 December 1999/ Accepted in revised form 25 April 2000     

Yeast population of the Kindo Peninsula lichens

Yeast abundance and species diversity in the lichens collected at the Kindo Peninsula (Karelia) were studied. A total of 14 lichen species analyzed belonged to the genera Bryoria, Cladonia, Hypogymnia, Icmadophila, Nephroma, Peltigera, and Ramalina. Abundance of cultured yeasts in lichens was intermediate between soil and phyllosphere. The average yeast number on lichens was ~2.5 × 10³ CFU/g, while it exceeded 8 × 10³ CFU/g on plants and reached only 1 × 10³ CFU/g in soil. Yeast population of different parts of Cladonia lichens was found to vary significantly in abundance, species diversity, and community structure. The highest yeast abundance and diversity were revealed in the growth zone. Fifteen yeast species were isolated from lichens, including 6 basidiomycetous and 9 ascomycetous ones. Unlike soils and plants, yeast population of lichens consisted mainly of ascomycetous species, with predominance of Candida sphagnicola and anamorphous yeasts of the genus Dothiora. These results show that yeasts from different taxonomic and ecological groups are a necessary component of lichens; conditions favoring the preservation and development of specific yeast communities differing from the typical soil and phyllosphere yeast complexes are formed in the lichens of northern taiga forests.     

Taxonomic diversity of aerobic organotrophic bacteria from clean vietnamese soils and their capacity for oxidation of petroleum hydrocarbons

The dominant species and abundance of the cultured aerobic organotrophic bacteria were determined in the clean soils of the Republic of Vietnam. The total number of organotrophs varied from 2.0 × 10⁵ to 5.8 × 10⁸ CFU/g soil. A considerable fraction of the bacterial population (1.1 × 10⁵–9.5 × 10⁶ CFU/g soil) was able to utilize petroleum hydrocarbons as the sole carbon and energy source. Most of the organisms obtained in pure cultures were gram-positive bacteria; over 70% were hydrocarbon-oxidizing organisms. Analysis of 16S rRNA gene sequences resulted in tentative determination of the taxonomic position of 22 strains, with 12 belonging to the Firmicutes, 4, to the Proteobacteria, and 6 to the Actinobacteria. The most common bacteria capable of hydrocarbon oxidation belonged to the genera Acinetobacter, Bacillus, Brevibacillus, Chromobacterium, Cupriavidus, Gordonia, Microbacterium, Mycobacterium, and Rhodococcus. Some of the isolated Bacillus and Staphylococcus strains, as well as one Pseudomonas and one Sinomonas strain, did not utilize hydrocarbons. Gram-positive degraders, especially members of the order Actinomycetales, which exhibited high hydrocarbon-oxidizing activity, gained competitive advantage in the presence of hydrocarbons. This microbial group probably plays an important role in hydrocarbon degradation in tropical soils. Thus, Vietnamese soils, which had no history of petroleum contamination, support numerically significant and taxonomically diverse populations of h ydrocarbon-oxidizing bacteria.     

Spore-forming bacteria in soil cultivated with GM white poplars: Isolation and characterization

The impact of transgenic white poplars (Populus alba L. cv. ‘Villafranca’) was assessed on the soil aerobic spore-forming bacteria (SFB). The genetically modified poplars, expressing either the StSy gene for resveratrol production or the bar gene for herbicide tolerance, were cultivated in greenhouse. The occurrence of SFB was monitored in soil samples collected at eight different timepoints over a two-year period. The total culturable bacterial population of the StSy and bar trials underwent significant seasonal fluctuations in the range of 10⁶−2.5 × 10⁸ CFU/g dry soil and of 10⁴−5 × 10⁸ CFU/g dry soil, respectively. Changes occurred also within the culturable SFB population with size varying at 10³−5 × 10⁴ CFU/g dry soil and 10²−2 × 10⁵ CFU/g dry soil in the StSy and bar trials, respectively. No significant differences in the size of the total and SFB culturable populations were observed when comparing each transgenic line with the nontransformed control line while seasonal shifts of soil bacterial populations were evident in both trials. The culturable SFB fraction included three isolates (SFB-1, SFB-2 and SFB-3) classified by 16S rDNA sequence analysis as members of the Bacillus genus. According to the reported data, cultivation of both herbicide-resistant and resveratrol-producing GM white poplars did not affect the culturable SFB population at the soil level.     

Development of emulsion from rhizobial fermented starch industry wastewater for application as Medicago sativa seed coat

Starch industry wastewater was efficiently employed for the production of Sinorhizobium meliloti and the concentrated culture was used for the development of a biofertilizer formulation. Tween‐80 (0.02 g/L) acted as the best emulsifier for a Sinorhizobium–canola oil emulsion. The stability of the emulsion and survival of the organism was enhanced by supplementation of xanthan gum at pH 8. The refrigerated condition was most favorable for stability and survival of the microorganism. The survival of microorganism at 4±1°C was 2.78×10¹⁰ and 2.01×10¹⁰ CFU (colony forming unit)/mL on storage for 1 and 2 months, respectively. The values were higher than the prescribed cell count (×10³ CFU/mL) for field application. At 40°C, the survival of bacteria reduced from 3×10¹⁰ CFU/mL to 8.1×10⁹ and 8.8×10⁶ CFU/mL in 1 and 2 months, respectively. Emulsion‐coated seed was incubated at different temperatures and a cell count of 10⁵ CFU/seed was observed after 2 months of storage at 4°C, which was equal to the highest level of the described requirement (10³–10⁵ CFU/seed). Emulsion supplemented with xanthan gum improved the shelf‐life under optimized conditions (Sinorhizobium concentrate – canola oil (1:1) emulsion with 0.02 g/L Tween‐80; storage at pH 8 and temperature 4±1°C) and this emulsion with the required cell count and prolonged viability was used for the pre‐inoculation of seed or for in situ soil application.     

峡谷型喀斯特不同生态系统的土壤微生物数量及生物量特征

采用样地调查与室内分析相结合的方法,研究了峡谷型喀斯特水田、旱地、草地、灌丛、人工林、次生林6种生态系统不同深度土壤微生物数量、微生物生物量特征及其分形关系。结果表明:峡谷型喀斯特不同生态系统的土壤微生物数量及组成不同,微生物数量均以次生林最高,旱地最低,其组成数量均为细菌放线菌真菌,细菌是土壤微生物的主要类群,数量多达26.66×105—71.64×105cfu/g,占全部微生物比例为87.00%—95.50%,其次为放线菌数量,为1.45×105—3.78×105cfu/g,所占比例为4.21%—12.39%,真菌数量最小,为0.07×105—0.23×105cfu/g,所占比例仅为0.24%—0.61%,不足1%。不同生态系统土壤微生物生物量碳(MBC)、氮(MBN)、磷(MBP)的含量不同,次生林MBC与MBN最高,人工林MBP最高,旱地MBC最低,草地MBN与MBP最低;各生态系统均为MBCMBNMBP。不同生态系统的MBC/SOC、MBN/TN、MBP/TP分别为0.44%—0.97%、2.13%—3.13%、1.46%—2.13%,差异不显著;MBC/MBN在3.06—6.54之间,其中次生林极显著高于其他生态系统,其他生态系统差异不显著。不同生态系统土壤微生物数量及生物量均随土层加深而减少,且具有良好分形关系,均达到了极显著水平(P0.01)。探讨土壤微生物活性为提高石灰土土壤肥力、促进喀斯特植被迅速恢复提供依据。     

抗感青枯病番茄的内生细菌数量动态分析及其对青枯病的生物防治

对番茄内生细菌数量动态及其对青枯病的生物防治研究结果表明:番茄内生细菌可来源于种子内部。番茄不同生育期,内生细菌数量最多在成株期,其中抗病品种根、茎分别为24.3×104CFU/g鲜重和22.9×104CFU/g鲜重,感病品种根、茎分别为9.8×104CFU/g鲜重和13.4×104CFU/g鲜重。抗病品种中具有拮抗青枯菌的内生细菌菌株为17个,感病品种中7个。部分内生细菌具促进番茄种子萌发和防治番茄青枯病的作用,其中5R和3R内生菌株的防病效果分别达91.7%和81.3%。     

Field evaluation of different application methods of the mixture of Bacillus cereus strain AR156 and Bacillus subtilis strain SM21 on pepper growth and disease resistance

The mixture of Bacillus subtilis strain SM21 and Bacillus cereus strain AR156, referred to as ASB, is a biopesticide in the process of registration in China, which has the capacity of controlling root-knot nematode in cucumber, Phytophthora wilt in pepper and Ralstonia wilt in tomato. In this study, we tested its effects on a range of physiological indicators of plant growth including biomass, yield, chlorophyll content and fruit nutrients of pepper, as well as, its efficacy in controlling bacterial wilt caused by Ralstonia solanacearum under field conditions in 2009 and 2010 by a variety of inoculation methods. Three application methods – soaking seeds, drenching soil around seeds right after sowing and drenching the rhizosphere of transplanted seedling with the aqueous solution (as a soil drench) –and three concentrations of ASB (1.0 × 10⁶ CFU/mL, 1.0 × 10⁷ CFU/mL, and 1.0 × 10⁸ CFU/mL) were employed. The results showed that both soaking seeds with ASB at 1.0 × 10⁷ CFU/mL as well as drenching rhizosphere with ASB at 1.0 × 10⁶ CFU/mL and 1.0 × 10⁷ CFU/mL promoted growth, increased yield and fruit nutrient contents of pepper. The combination of these two inoculation methods led to significant increases in growth and fruit nutrient contents. We found that the most effective way was the combination of soaking seeds with the ASB at 1.0 × 10⁷ CFU/mL and drenching rhizosphere with it at 1.0 × 10⁶ CFU/mL, which is also easy for Chinese farmers to implement.     

Effects of long-term chlorimuron-ethyl application on the diversity and antifungal activity of soil Pseudomonas spp. in a soybean field in Northeast China

The herbicide chlorimuron-ethyl has been applied widely for weed control in farmland, especially in soybean fields in China over the past decade, but the chronic effects of this herbicide on soil microorganisms, particularly Pseudomonas spp., is not well understood. Taking a continuously cropped soybean field in the town of Fuyuan—a soybean production base of Heilongjiang Province in Northeast China—as a case study, soil samples were collected from plots having received 0-, 5-, and 10-year applications of chlorimuron-ethyl (30 g active component of chlorimuron-ethyl/ha/year) to study the abundance and diversity of Pseudomonas spp. Meanwhile, an in vitro assay was used to examine the antifungal activities of isolated Pseudomonas spp. against soil-borne pathogens (Fusarium graminearum, Fusarium oxysporum, and Rhizoctonia solani) causing soybean root rot disease. The production of siderophore, hydrogen cyanide (HCN), and lytic enzymes (cellulase, pectinase, and chitinase) by Pseudomonas spp. was also investigated. With 5- and 10- year chlorimuron-ethyl application, the numbers of soil Pseudomonas spp. decreased from 121?×?10² CFU/g dry soil in the control to 40?×?10² CFU/g dry soil and 13?×?10² CFU/g dry soil, and the Shannon index values decreased from 6.23 to 3.71 and 1.73, respectively. The numbers of antifungal Pseudomonas spp. also decreased, and the proportions of Pseudomonas spp. with antifungal activities against the different test pathogens altered. All the antifungal Pseudomonas spp. could produce siderophore and HCN but not lytic enzymes. The results suggest that long-term application of chlorimuron-ethyl in continuously cropped soybean field had negative effects on the abundance and diversity of soil Pseudomonas spp., including species with different antifungal activities against pathogens. Siderophore and HCN rather than lytic enzymes formed the antifungal metabolites of Pseudomonas spp., and the number of antifungal Pseudomonas that can produce siderophore and HCN decreased markedly under application of chlorimuron-ethyl, especially after 10-year application.     

Occurrence in Soil and Primary Infections of Pseudomonas corrugata Roberts and Scarlett

The occurrence of Pseudomonas corrugata in soil has been checked. Semiselective medium TNR (a modified SNR) permitted to isolate the causal agent of “tomato pith necrosis” from that source. The average soil population of the bacteria was 3.1 × 10⁴ CFU × g of soil. P. corrugata was also isolated from plants sowed in the naturally infected soil. It was supposed that primary infections came from here.     

金龟子绿僵菌在森林土壤中的分布及对松墨天牛致病性测定

松墨天牛是重大森林植物检疫性病害——松材线虫病的主要媒介昆虫。本研究于2005年8月～2006年8月从福建、江西两省共110个林分样区(其中松林88个样区)采集土壤样品330份,采用选择性培养基分离土壤中的金龟子绿僵菌。从21个样区的26份土样中分离出的金龟子绿僵菌占采集样区的19．1％和样品的7．9％,成菌落数(CFU)500～72500CFU/g,表明金龟子绿僵菌在森林土壤中有较为广泛的分布。对分离到的9个产孢量高的菌株,采用浸渍法(1×10~7孢子/mL)接种3～4龄健康松墨天牛幼虫,采用跗节接种法接种2～15日龄健康成虫,测定其致病力。结果表明,MaYTTR-03、MaYTTR-04菌株对松墨天牛幼虫和成虫均有较高致病力,表现出良好的生防潜力。     

金龟子绿僵菌在森林土壤中的分布及对松墨天牛致病性测定

松墨天牛是重大森林植物检疫性病害——松材线虫病的主要媒介昆虫。本研究于2005年8月～2006年8月从福建、江西两省共110个林分样区（其中松林88个样区）采集土壤样品330份,采用选择性培养基分离土壤中的金龟子绿僵菌。从21个样区的26份土样中分离出的金龟子绿僵菌占采集样区的19.1%和样品的7.9%,成菌落数（CFU）500～72500CFU/g,表明金龟子绿僵菌在森林土壤中有较为广泛的分布。对分离到的9个产孢量高的菌株,采用浸渍法（1×10⁷孢子/mL）接种3～4龄健康松墨天牛幼虫,采用跗节接种法接种2～15日龄健康成虫,测定其致病力。结果表明,MaYTTR-03、MaYTTR-04菌株对松墨天牛幼虫和成虫均有较高致病力,表现出良好的生防潜力。     

Evaluation of a New Tumor Necrosis Factor-α-Inducing Membrane Protein of Helicobacter pylori as a Prophylactic Vaccine Antigen

Background: Tumor necrosis factor (TNF)‐α‐inducing protein (Tipα) is a newly identified carcinogenic factor present in Helicobacter pylori. Tipα has the unique function of inducing TNF‐α production by gastric cells in vitro and is assumed to be related with the development of gastritis and gastric cancer. We investigated the effects of vaccination with Tipα against H. pylori infection and analyzed the immune responses. Methods: C57BL/6 mice were immunized via the intranasal route with CpG, recombinant Tipα + CpG, and recombinant del‐Tipα (a mutant of Tipα) + CpG. Eight weeks after the mice were infected with H. pylori (5 × 10⁷ CFU), the number of colonizing bacteria in the stomach was calculated, and the histological severity of gastritis was evaluated. Levels of Tipα‐specific IgG and IgA antibodies in mouse serum were measured by an enzyme‐linked immunosorbent assay (ELISA). Local production of cytokines including Interleukin (IL)‐10, TNF‐α and Interferon (IFN)‐γ in gastric mucosa was also measured by real time‐PCR. Results: Levels of Tipα‐specific antibodies were significantly higher in Tipα‐immunized and del‐Tipα‐immunized mice than in the infection control group. The numbers of colonizing bacteria were significantly reduced in Tipα‐immunized mice (4.29 × 10⁵ CFU/g) and del‐Tipα immunized mice (2.5 × 10⁵ CFU/g) compared with infection control mice (5.7 × 10⁶ CFU/g). The levels of IFN‐γ and IL‐10 were significantly higher in del‐Tipα‐immunized mice than the infection control group. Conclusion: Vaccinations with Tipα and del‐Tipα were effective against H. pylori infection. The inhibition of H. pylori colonization is associated mainly with Th1 cell‐mediated immunity.     

Response Surface Optimization of Lyoprotectant for Lactobacillus bulgaricus During Vacuum Freeze-Drying

The individual and interactive effects of skimmed milk powder, lactose, and sodium ascorbate on the number of viable cells and freeze-drying survival for vacuum freeze-dried powder formulation of Lactobacillus bulgaricus were studied by response surface methodology, and the optimal compound lyoprotectant formulations were gained. It is shown that skim milk powder, lactose, and sodium ascorbate had a significant impact on variables and survival of cultures after freeze-drying. Also, their protective abilities could be enhanced significantly when using them as a mixture of 28% w/v skim milk, 24% w/v lactose, and 4.8% w/v sodium ascorbate. The optimal freeze-drying survival rate and the number of viable cells of Lactobacillus bulgaricus were observed to be (64.41 ± 0.02)% and (3.22 ± 0.02) × 10¹¹ colony-forming units (CFU)/g using the optimal compound protectants, which were very close to the expected values 64.47% and 3.28 × 10¹¹ CFU/g.     

Evaluation of waste chicken feathers as peptone source for bacterial growth

Aims: Peptones are one of the most expensive constituents of microbial media. This study was undertaken to prepare the peptone from waste chicken feathers through a new process. Methods and Results: The chemical analysis of chicken feather peptone (CFP) was performed. The ability of CFP to support the growth of the three test bacteria in liquid and agar media was comparable to those of three commercial peptones [tryptone peptone (TP), fish peptone and protease peptone (PP)]. Conclusions: CFP was found to be rich in ash (42·1 g 100 g^?1), protein (55·8 g 100 g^?1) and mineral contents. The maximum biomass yield (3·13 g l^?1) and colony number (83 × 10⁸ CFU ml^?1) for bacterium Bacillus subtilis were attained with CFP. The maximum biomass yields and colony numbers for Lactobacillus delbrueckii ssp. bulgaricus and Escherichia coli were reached in TP medium. Second high biomass yield (2·64 g l^?1) and colony number (75 × 10⁸ CFU ml^?1) for E. coli were achieved using CFP. Third high biomass yield (1·29 g l^?1) and colony number (90 × 10⁷ CFU ml^?1) for Lact. delbrueckii ssp. bulgaricus were obtained in CFP medium. Significance and Impact of the Study: Usability of waste chicken feathers as substrate for bacteria was investigated for the first time in the present study. The peptone may be used in industrial fermentations for production of antibiotics, organic acids, enzymes and biopolymer. It may be also used in clinical microbiology. A new chemical process was developed for peptone preparation. This process may be also employed for peptone preparation from other organic materials, especially fibrose protein‐containing materials.     

Hydrochemical,bacteriological assessment,and classification of groundwater quality in Thulamela Municipality,South Africa: potential health risk

Abstract

Potential effects of anthropogenic activities on different boreholes around Thulamela Municipality, South Africa, were evaluated by quantifying the bacteria indicators and physicochemical parameters during summer, autumn, and winter. The purpose was to determine whether the borehole water in this region is safe for domestic use across the seasons. The concentrations of physicochemical (Temperature, pH, electrical conductivity (EC), turbidity, and nitrate) and bacteriological (both Escherichia coli and Enterococcus faecalis) contaminants in the borehole water samples were determined using standard microbiology methods. The mean concentration of NO₃ for most of the boreholes failed to comply with the recommended guidelines throughout the season. High microbial load of E. coli (2.0?×?10¹ – 4.6?×?10³ CFU/100?ml) and E. faecalis (2.0?×?10° – 6.0?×?10² CFU/100?ml) was recorded in the wet season than in the dry season (0.0 – 7.0?×?10² and 0.0 – 1.0?×?10¹ CFU/100?ml, respectively). Sanitary inspection and water source classification showed that most boreholes are prone to chemical contaminants during summer and autumn due to rainfall and this correlates with the measured microbial contamination. The result is significantly important because water from these boreholes is used for domestic purposes without treatment and could pose major public health risks to the consumers.     

The assessment of airborne microorganisms in large-scale composting facilities and their immediate surroundings

The number of airborne microorganisms in the area of large-scale composting facilities with different composting techniques (A: open facility using the intensive decomposition process [4000 t/year]. B: closed facility with compost containers [7000 t/year], C: closed facility with table-pile compositing and automatic turning equipment [22 000 t/year]) was investigated using impactor sampling systems (Andersen samplers). All counts carried out inside the closed facilities, especially during the turning process, showed values of >5.0 × 10⁵ CFU/m³ for viable bacteria and moulds with a proportion ofAspergillus fumigatus of up to 64%. Depending on the type of facility, different median values were determined inside the plant area. Counts were highest in the immediate area around the biofilter outside of Facility C (1.7 × 10⁴ CFU/m³ for bacteria and 9.5 × 10³ CFU/m³ for moulds). In view of the high load of ambient airborne microorganisms inside the composting facilities, adequate occupational health measures are urgently required. Counts determining the hazard to neighbourhood residents at distances of between 150 and 2000 m showed, depending on the facility, annual median values of 170–330 CFU/m³ for bacteria, 75–340 CFU/m³ for moulds, and 15–52 CFU/m³ forA. fumigatus. Higher individual counts — up to 3 × 10³ CFU/m³ for moulds and up to 350 CFU/m³ forA. fumigatus — were found as a result of specific climatic influences, (e.g. winds) and activities as well poor operation. Given the high proportion ofA. fumigatus in the exhaust air, this mould can serve as an indicator for the evaluation of the health risk. However, the maximum values found in the present study, may also be caused by other events in rural areas, (e.g. agricultural activities). With regard to neighbourhood residents, odour complaints are more important than pollution by microorganisms.