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Microbiological Corrosion of Buildings in Everyday Practice – Examples
Published in Rafał L. Górny, Microbiological Corrosion of Buildings, 2020
The use of wood, cardboard or cork as finishing or insulating materials may cause additional microbial and bacterial toxin emissions in an indoor environment [Cox and Wathes 1995; Pope et al. 1993]. The analysis of samples of these materials shows that under favourable humidity conditions, they may contain up to 107 CFU/g of microorganisms, and endotoxin concentration may reach 105–106 EU/g [Dutkiewicz 1989]. The microorganisms colonising these materials include Gram-negative bacteria (Pantoea agglomerans, Agrobacterium radiobacter, Pseudomonas fluorescens, Xanthomonas maltophilia, Acinetobacter calcoaceticus), corynebacteria, Bacilli, yeasts (e.g. of Candida, Cryptococcus, Rhodotorula genera) and moulds (e.g. Penicillium spp., Aureobasidium pullulans, Aspergillus fumigatus, Trichoderma spp.) from wood [Dutkiewicz et al. 1992], as well as Aureobasidium spp. and Streptomyces spp. from cork [Pope et al. 1993].
Biological Agents
Published in Katarzyna Majchrzycka, Małgorzata Okrasa, Justyna Szulc, Respiratory Protection Against Hazardous Biological Agents, 2020
Streptococcus suis isolated from pigs, and less frequently from ruminants and other animals such as dogs, cats and birds, also poses an occupational hazard in agricultural working environment [Wertheim 2009]. S. suis genus bacteria can cause zoonotic bacterial meningitis, arthritis, pneumonia, endocarditis and deafness in humans [Bartelink 1995]. In turn, Campylobacter sp. bacteria, which often inhabit the digestive system of farm animals, may cause a disease (campylobacteriosis) in the form of enteritis and gastritis in farmers. Acinetobacter calcoaceticus, Alcaligenes faecalis, Pasteurella aerogenes, Pantoea agglomerans and Rahnella are also responsible for infections in people working in agricultural working environment [Ejlertsen 1996; Milanowski 1998]. Moreover, gram-negative bacilli, Alcaligenes faecalis and Pantoea agglomerans, and gram-positive bacteria Arthrobacter globiformis and Agromyces ramosus, are a source of highly biologically active allergens, which may cause HP. What is more, there are indications that Pantoea agglomerans may cause occupational dermatoses. In turn, Rahnella bacteria, with wood and wood dust being their reservoir, are a frequent cause of occupational allergies in workers of wood warehouses, foresters and sawmills, and in carpenters.
Role of Microbes in Solid Waste Management
Published in Ashok K. Rathoure, Zero Waste, 2019
Vermicomposting of organic wastes is greatly facilitated by diverge microbial population which are already present in the waste material, soil and also in the gut of earth worms employed for composting. Free living nitrogen-fixing microbes belonging to the genera Azospirillum, Azotobacter, Autotrophic Nitrosomonas, Nitrobacter and so forth help in promoting plant growth by nitrifying the soil, and phosphate-solubilizing bacteria such as Pantoea agglomerans, Microbacterium laevaniformans and Pseudomonas putida help in plant disease suppression (Gopal et al., 2009). On the other hand, Pseudomonas oxalaticus helps in oxalate degradation and Bacillus spp., B. megaterium, B. pumilus and B. subtilise show antimicrobial activities against certain microbial pathogens (Vaz-Moreira et al., 2008). The detailed role of some of the microbes in vermicomposting is shown in Table 9.1.
Effect of skimmed milk powder concentrations on the biological characteristics of microencapsulated Saccharomyces cerevisiae by vacuum-spray-freeze-drying
Published in Drying Technology, 2020
Lin Cao, Qinglian Xu, Yage Xing, Xunlian Guo, Wenxiu Li, Yimin Cai
Microencapsulation is widely used by embedding core materials such as microorganisms and other bioactive substances into carrier materials. This offers the protection to unstable materials against heat, oxygen, light, and humidity in the external microenvironment.[7–13] Methods such as spray-drying and vacuum-freeze-drying are widely used for microencapsulation preparation. Spray-drying involves the technology where the polymeric solution is atomized with the active materials in the drying chamber. This process leads to the evaporation of the solvent to form microcapsules. The product derived from this process can be widely applied in various processes due to its flexibility and low cost.[12,14,15] However, during the drying process, bacterial cultures could be exposed to the high temperature used for product dehydration, which might destroy the metabolic activity of microbial cells.[16–18] According to Costa et al.,[16] the Pantoea agglomeranss train displayed exceptional sensitivity, and the live bacteria rate was less than 8% during the spray-drying process. On the other hand, freeze-drying is a more economical, uncomplicated, and safer method for the conversion of liquids into ice crystals. The ice is subsequently moved by sublimation without the multiple solvent exchanges.[13,19,20] Although it was possible to produce the microbial agents with a high rate of live bacteria, the procedure took much longer to complete and the cost was significantly higher when compared to spray-drying.[13,19–22] Therefore, in order to reduce the drying time and costs as well as to control the characteristics, the spray-freeze-drying (SFD) technique was used. This method combines the advantages of both spray-drying and freeze-drying.