scholarly journals Determination of the biodegradability of chitosan utilizing the most probable number technique

2020 ◽  
Vol 42 ◽  
pp. e52965
Author(s):  
Wender Cardoso Silva ◽  
Ilva de Fátima Souza ◽  
Vivian Machado Benassi ◽  
Juan Pedro Bretas Roa ◽  
Paulo Henrique Graziotti ◽  
...  

The present work aimed to evaluate the degradability of the chitosan polymer by soil microorganisms. This evaluation was accomplished using the Most Probable Number (MPN) method by plating in drops so that soil microorganisms capable of degrading the polymeric material could be quantified. Soil samples diluted in three specific culture media for each type of microorganism were plated – bacteria, fungi and actinobacteria – and they were maintained at 28°C for seven days to determine the growth rate of fungi and actinobacteria, and for 48 hours for the development of bacteria. Significant differences in the MPN of actinobacteria relative to the other groups analyzed were observed. Thus, the method used was effective for determining the degradability of the chitosan biopolymer when observing the development of microorganisms subjected to the replacement of the carbon source by the addition of 2% w v-1 of the chitosan biopolymer to the culture medium. The formation of clear regions around the microbial colonies was a strong indicator of biodegradation.

1985 ◽  
Vol 31 (8) ◽  
pp. 686-692 ◽  
Author(s):  
A. H. Havelaar ◽  
M. During ◽  
E. H. M. Delfgou-Van Asch

The recovery of Pseudomonas aeruginosa on several selective culture media was tested using raw sewage and secondary sewage effluent samples as well as spiked chlorinated imitation swimming water and samples from whirlpools. mPA-medium B gave good recovery of both vital and chlorine-injured P. aeruginosa and selectivity was greater than 90% when analysing whirlpool samples. It is therefore the medium recommended for examination of chlorinated swimming pools. When analysing sewage polluted water with the mPA-B medium, reduced selectivity was noted from low verification rates and from overgrowth by competitive flora. A modified medium (mPA-D; addition of cetrimide, omission of sulphapyridine and actidione) was more selective and sufficiently recovered noninjured cells. Chlorine-injured cells were completely inhibited, however. C-390 (9-chloro-9-(4-diethylaminophenyl)-10-phenylacridan) was confirmed to be highly selective for P. aeruginosa when used in spread plates at a concentration of 30 μg/mL; P. aeruginosa was slightly inhibited. However, the medium could not be used with conventional membrane filtration techniques, because cellulose ester filters interfered with the selective action of C-390. Selectivity could be improved by using Gelman Tuffryn (polysulphone) filters and increasing the C-390 concentration to 120 μg/mL. At this concentration, however, the medium was strongly inhibitory to P. aeruginosa; resuscitation only partially improved recovery. Two other membrane filtration media were tested. Both cetrimide – nalidixic acid agar and Drake's medium No. 19 were inhibitory to chlorine-injured cells. Several types of membrane filters were tested and there was little difference between them. In the most-probable-number technique, recovery of P. aeruginosa was shown to be excellent when using asparagine broth. Malachite green broth was strongly inhibitory to chlorine-injured P. aeruginosa.


2003 ◽  
Vol 41 (7) ◽  
pp. 2992-3000 ◽  
Author(s):  
T. K. Beattie ◽  
D. V. Seal ◽  
A. Tomlinson ◽  
A. K. McFadyen ◽  
A. M. Grimason

2019 ◽  
Vol 9 (2) ◽  
pp. 112
Author(s):  
SAWIDYA FITRIYANI ◽  
I WAYAN DANA ATMAJA ◽  
NI NENGAH SONIARI

Algae Genus in Organic Rice Fields Planted with Local and Inhibrida Rice in Subak Jatiluwih, Tabanan. The abundance of microalgae in rice fields, especially microalgae from Cyanophyta division that are capable of fixing nitrogen, is very important helping maintain soil fertility. The aim of this study was to find out the genus of algae in organic rice fields of Subak Jatiluwih, Tabanan. The research was conducted from September 2018 to April 2019. Sampling was done in Subak Jatiluwih. Algae breeding were carried out at Biology and Physics Laboratory, Faculty of Agriculture, Udayana University. This research method uses descriptive quantitative. The implementation of the research included the determination of location, soil and water sampling, identification of algae, and analysis of algae genera. Enrichment algae was carried out using the MPN method, results of the analysis of algae genus were found in 37 genera from 3 divisions i.e Chlorophyta, Cyanophyta and Chrysophyta. Descriptive quantitative method Most Probable Number (MPN) calculation conclude that there are not much different from the Local and Inhibrida rice fields. The maximum population algae of local rice fields is 1.100 cell g-1 and Inhibrida rice fields is >1.100 cell g-1 of land. The minimum population is 3,6 cell g-1 of land in local rice fields, and 9,2 cell g-1 of land in Inhibrida rice fields.


AGROFOR ◽  
2016 ◽  
Vol 1 (3) ◽  
Author(s):  
Veronika KUKUČKOVÁ ◽  
Nina MORAVČÍKOVÁ ◽  
Radovan KASARDA

The aim of this study was to assess genetic structure of Slovak Pinzgau populationbased on polymorphism at molecular markers using statistical methods. Femaleoffspring of 12 most frequently used bulls in Slovak Pinzgau breeding programmewere investigated. Pinzgau cattle were found to have a high level of diversity,supported by the number of alleles observed across loci (average 5.31, range 2-11)and by the high within-breed expected heterozygosity (average 0.66, range 0.64-0.73). The state of genetic diversity is satisfying and standard for local populations.Detection of 12 possible subpopulation structures provided us with detailedinformation of the genetic structure. The Bayesian approach was applied, detectingthree, as the most probable number of clusters. The similarity of eachsubpopulation using microsatellites was confirmed also by high-throughputmolecular data. The observed inbreeding (FROH=2.3%) was higher than thatexpected based on pedigree data (FPED=0.4%) due to the limited number ofavailable generations in pedigree data. One of the most important steps indevelopment of efficient autochthonous breed protection programs ischaracterization of genetic variability and assessment of the population structure.The chosen set of microsatellites confirmed the suitability in determination of thesubpopulations of Pinzgau cattle in Slovakia. The state of genetic diversity at moredetailed level was successfully performed using bovineSNP50 BeadChip.


2020 ◽  
Vol 36 (2) ◽  
pp. 75-77
Author(s):  
Anindita Bhowmik ◽  
Sunjukta Ahsan

Majority of the population of Bangladesh depend on tap or surface water as their source of water supply. This study was carried out to examine the microbial quality of both water and soil collected from different places using the multiple tube fermentation technique to determine coliform count by the most probable number (MPN) method in brilliant green lactose broth (BGLB) media.Inoculum from positive tubes of the presumptive test were further transferred on eosinemethylene blue (EMB) and MacConkey agar.The organisms isolated were further characterized using biochemical tests. Out of 93 water samples, 30 (32.26%) indicated the presence of lactose fermenter and gas producer in all 3 tubes of dilution series using inoculum quantities of 1.0, 0.1 and 0.01 ml, whereas out of 85 soil samples, 45 (52.94%) showed acid and gas production in all 3 tubes of dilution series.Among 85 soil samples, 40 samples that contained at least one positive in each dilution series and among 93 water samples, 31 samples that contained at least one positive in each dilution series were further re-identified with biochemical tests.This study showed 30.59% soil isolates and 26.88% water isolates were Escherichia coli which highlighted the fact that both water and soil act as a major reservoir of E.coli, which indicates possible fecal contamination as well as presence of potentially pathogenic E. coli. Bangladesh J Microbiol, Volume 36 Number 2 December 2019, pp 75-77


1995 ◽  
Vol 78 (6) ◽  
pp. 1525-1529 ◽  
Author(s):  
Mjtsuko Taba Ohara ◽  
Takako Saito

Abstract An alternative method was developed for counting viable microbial contaminants in pharmaceuticals and cosmetics with insoluble materials and low bioburden. The method uses triphenyltetrazolium chloride (TTC). The inhibitory effect of TTC on microbial growth observed by others was eliminated by adding it as an overlay, after incubation of sample in culture medium for 48 h. Six samples of pharmaceutical suspensions and 6 samples of cosmetics were evaluated by most-probable number (MPN) and pour-plate techniques with TTC in comparison with MPN with subculturing. The equivalence between MPN technique with TTC and subculturing was demonstrated for all samples and between pour-plate and subculturing for 10 samples. The differences were probably due to some error inherent to both techniques and not from application of TTC. Comparison of coefficients of variation showed that plate countings were more precise than the MPN method, as expected.


1978 ◽  
Vol 24 (5) ◽  
pp. 552-557 ◽  
Author(s):  
A. L. Mills ◽  
C. Breuil ◽  
R. R. Colwell

Several media designed for use in a most probable number (MPN) determination of petroleum-degrading microorganisms were compared. The best results, i.e., largest numbers, were obtained using a buffered (32 mM PO4≡) liquid medium containing 1% hydrocarbon substrate. Of 104 presumptive oil degraders tested, 20 grew on oil agar medium but did not utilize oil or a mixture of pure paraffinic hydrocarbons (C10 to C16n-alkanes) in liquid (MPN) medium. Visible turbidity in the liquid medium was correlated with hydrocarbon utilization. Counts of petroleum degraders obtained using liquid medium (MPN) were in most cases higher than those obtained on an oil-amended silica gel medium. Both procedures yield an estimation of oil degraders, and the oil-amended agar permits growth of organisms which do not degrade crude oil. All strains of oil-degrading microorganisms examined in this study were lipolytic, but the converse was not always true.


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