scholarly journals A two-parameter model for the determination of the partition coefficient for TRS in a culture medium

2022 ◽  
Vol 52 (1) ◽  
pp. 15-20
Author(s):  
Javier Silva ◽  
Rodrigo Ortiz ◽  
Samuel Carrasco ◽  
German Aroca

A two-parameters model was applied for the determination of the activity coefficient for a culture medium, and compared with Henry's law, the extended UNIQUAC, and experimental data obtained from an experimental setup system, consisting of a liquid culture media Thiobacillus (ATCC 290) with hydrogen sulfide (H2S), dimethyl sulfide (DMS), methyl mercaptan (MM), and dimethyl disulfide (DMDS), respectively.  The ANOVA indicates that the use of Henry's law is not appropriate for MM and H2S with R2adj values of -106.15% and -53.33%, respectively. The extended UNIQUAC model and the two-parameter model were able to describe the system with values of 76.94% and 94.15% for DMS and DMDS in the case of UNIQUAC Extended, respectively, and 88.50% and 98.08% using the two-parameter model.   These results show that the two-parameter model is able to describe the system, using a low number of parameters. However, the extended UNIQUAC shows better results but presenting a high level of over-parameterization. Henry's law showed significant deviations, not being representative of all analyzed cases.  The two-parameter model is presented as an alternative to describing systems in which vapor-liquid mass transfer is involved in culture media, providing a better approximation than traditional models and lower calculation costs than complex models.

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.


2000 ◽  
Vol 34 (21) ◽  
pp. 4554-4559 ◽  
Author(s):  
Michael D. David ◽  
Nicholas J. Fendinger ◽  
Vincent C. Hand

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