Georgian Scientists/ . 7 N 4, 2025 440 Georgian Scientists Vol. 7 Issue 4, 2025 https://doi.org/10.52340/gs.2025.07.04.25 Microbiological analysis of wastewater, fruit juices, determination of microbial sizes, diagnostics and filtration of microorganisms 1George Bibileishvili, 2Manana Mamulashvili, 3Elene Kakabadze, 4Liana Ebanoidze, 5Nona Butkhuzi, 6Ia Gogiberidze Engineering Institute of Membrane technologies of Georgian Technical University 1Doctor of Chemical and Biological Engineering, Chief Scientist, email: 75bibileishvili@gmail.com ORCID ID: https://orcid.org/0009-0003-7712-2436 2Doctor of Chemical and Biological Engineering, Senior Research Scientist, email:mananamamula59@gmail.com ORCID ID: https://orcid.org/0009-0001-3982- 5515 Abstract The paper studies the microbiology of water and apple juice from the Mtkvari River. Various types of bacteria (Escherichia coli, Enterococcus Faecalis, Pseudomonas aeruginosa) were found in the water, which indicates the pollution of the Mtkvari River, while the study of apple juice revealed bacterial (Bacillus subtilis, Lactobacillus spp,) microflora, and the sizes of the microbes were determined. The reliability of ultrafiltration, which completely removes contaminants, improves the quality of water and fruit juice, has been established. Keywords: water, fruit juices, microbiology, diagnostics, ultrafiltration Introduction The Mtkvari River basin creates an important living environment for domestic and industrial facilities in and outside Tbilisi. The main source of river pollution is municipal wastewater. Wastewater leads to deterioration of chemical and biological indicators of river water quality, disrupts the biodiversity of aquatic ecosystems and causes microbiological pollution. Microbiological analysis has determined the types and quantities of microorganisms, which determine the water quality and ecological status of the Mtkvari River and indicates possible epidemiological risks [1,2]. In fruit juices, the natural sugars, acidity and high water activity contribute to the development of both beneficial and pathogenic microbes. Membrane processing of fruit juices is carried out on an industrial scale to replace the stages of depth filtration, Georgian Scientists/ . 7 N 4, 2025 441 decantation and partial evaporation. Membrane filtration is an effective method for purifying juices, resulting in a crystal-clear permeate [3]. Purpose and analysis of the work The purpose of the study is to study the contaminating microbes present in the water of the Mtkvari River and apple juice, for which cultivation was carried out on various nutrient media and their characteristics were studied. Technological conditions of baromembrane processes were developed for the disinfection and sterilization of solutions. To detect microbes, incubation was carried out at 22-37°C for 24-72 hours. The Mtkvari River sample was taken in Tbilisi according to the international ISO 5667-10 standard for water sampling. For microbiological research, the standard ISO 9308-1:2014 direct seeding and membrane filtration method was used [4,5,6]. We cultivated microbes in Petri dishes on dense nutrient media. We used chromogenic coliform (CCA), endo and nutrient agar as culture media for microorganisms. Microbe sizes were determined with an accuracy of 1 m using a polarizing interference optical microscope (Biolar) with an objective micrometer division of 10 m [7,8]. The water samples of the Mtkvari River were filtered through a membrane with a pore size of 0.1 m, and apple juice through a membrane with a pore size of 0.45 m. Conclusions and judgment As a result of the inoculation of water samples on a nutrient medium, E-coli was detected as a typical blue color, and coliform as a pinkish-reddish oxidase-negative colony. The results of the study are expressed by measuring the number of colony-forming units in a volume considered standard for microorganisms. The results of the analysis of water from the Mtkvari River are given in Table 1; Table 1. Number of microbes in the water of the Mtkvari River Indicator to be investigated Unit of measurement Allowed quantity Result before filtering Result after filtering Mesophilic aerobes and facultative anaerobes 37 22 In 1 ml 20 100 15 40 Not found Not found Common coliform bacteria Goat/300 ml It doesn't work. 2400 Not found Escherichia coli Goat/300 ml Will not be allowed 2200 Not found Streptococcus faecalis Goat/250 ml Will not be allowed 300 Not found Pseudomonas aeruginosa Goat/250 ml Will not be allowed 1700 Not found Sulfite-reducing clostridia (Cl perfringens) Goat/50 ml Will not be allowed 40 Not found Georgian Scientists/ . 7 N 4, 2025 442 The indicators of microorganisms found in the Mtkvari River indicate fecal pollution. Their characteristics are presented in Table 2. Table 2. Characteristics of microorganisms present in the Mtkvari River sample Characteristic Escherichia coli Streptococcus faecalis Pseudomonas aeruginosa Form Round Round Irregular Color Pink Black-dark Green-cyan Surface Glossy Smooth Shiny Consistency Soft Soft Adhesive Size in m 2,0 -3,0 1,5 3,0 – 4,0 The results of the microbiological study of apple juice are given in Table 3. Table 3. Characteristics of microorganisms present in apple juice sample Juice Colony type Total number of cells/ml Form Color Surface Microscopic characteristics Before filtration After filtration Apple Bacteria 2600 Not found Round White Smooth Bacillus subtilis (size 3,0 -5,0 m) As the results show, fecal contamination was detected in the water of the Mtkvari River, which in itself negatively affects the quality of the river's water, while as a result of ultrafiltration, no contaminants were detected in either the Mtkvari River water or the apple juice filtrate. Conclusion The study showed that the number of microbes found in the water of the Mtkvari River indicates potential sanitary hazards, while bacterial microflora was detected in apple juice. It was determined that ultrafiltration improves the transparency and quality of water and fruit juices, resulting in microbiologically clean water and juice. References 1. Bibileishvili G.V., Mamulashvili M.A., Javashvili Z.D., Kakabadze E.G. Microbiological study of natural fresh waters treated with ultrafiltration membranes. Georgian Engineering News Vol.93 2 2021 pp. 113-114 2. Bibileishvili G.V., Mamulashvili M.A., Javashvili Z.D., Butkhuzi T.G. Microbiological study of Black Sea water and application of ultrafiltration method to provide Georgian Georgian Scientists/ . 7 N 4, 2025 443 resort zone with ecologically clean water. Georgian Engineering News Vol. 93 2 2021 pp. 115-117 3. Manana Mamulashvili1, Giorgi Bibileishvili2, Zaza Javashvili3, Tinatin Butkhuzi4, Elene Kakabadze5 Determination of morphological and tinctorial characteristics of microorganisms in wine and water. Georgian Scientists Vol.7 No.2 https://doi.org/10.52340/gs.2025.07.02.59 pp. 648-651 4.Georgian National Environment Agency – Water Quality Reports (2023). 5. ISO 5667-1 Water quality - Water sampling guide. 6. ISO 9308-1 (2014). Water quality Enumeration of Escherichia coli and coliform bacteria - Part 1: Membrane filtration method for waters with low bacterial background flora 7. G. Bibileishvili, N. Gogesashvili, M. Kezherashvili, L. Kuparadze, M. Mamulashvili, L. Ebanoidze Micro- and ultrafiltration processing of water and fruit juices. Collection of abstracts of the International Conference "Chemistry - Achievements and Prospects" dedicated to the 90th anniversary of the birth of Academician Givi Tsintsadze GTU Tbilisi 2023 8. G. Bibileishvili, M. Mamulashvili M. Kezherashvili Z. Javashvili E. Kakabadze Baromembrane processing of grape and tangerine juices Georgian Chemical Journal ISSN 1512-0686 VOL.19 1 2019 pp.91-92 , , , 1 , 2 , 3 , 4 , 5 , 6 . (Escherichia coli, Enterococcus Faecalis, Pseudomonas aeruginosa), , , (Bacillus subtilis, Lactobacillus spp,) , . , , . : , , , , ,