Kinetic Study of the Fermentation of Soursop Juice Using Saccharomyces Cerevisiae with Effect of Succinic Acid
C Ogbebor1*, A C. Ogonegbu1
1Department of Science Education, Enugu State University of Science and Technology (ESUT), Enugu, Nigeria
* Corresponding author: C Ogbebor
Abstract
The fermentation of soursop juice as substrates by Saccharomyces cerevisiae (yeast) was investigated to obtain certain useful kinetic parameters. These were achieved by the determination of the effects of temperature, yeast, pH, substrate and inhibitor on the rate of carbon (IV) oxide (CO2) production. The extent of inhibition was examined by the additio n of succinic acid. The results indicate that the rate of fermentation increased in proportion with temperature (optimum 36oC), substrate (optimum 50%v/v) and succinic acid (optimum 30%v/v) up to a limit and decreased. This suggests that the reaction takes place in two steps (equilibrium and decomposition steps). The kinetic parameters examined are: maximum velocity of reaction, V max for substrate, 2.58x102M1min-1 and succinic acid, 1.00x10 2M1min-1. Catalytic constant, k 2; for substrate, 8x10 - 2min-1 and succinic acid, 6.0x10 -2min-1. Overall rate constant k, for substrate, 1.79x10 2 and succinic acid, 1.09x102. The order of initial reaction is first order for substrate and the additive. The dissociation constants of enzyme -substrate complexes, k s are 1.64x102 and succinic acid, 2.40x10-1. The Michaelis constant, k m for the substrate, 1.64x10 2 M and succinic acid, 2.50x10 -1. The specific activity of enzyme for the substrate is 1x10 -1 and succinic acid, 2x10 -2. Finally, the type of inhibition was found to be uncompetitive from the extrapolated Lineweaver-Burk plots and the suggested inhibitor did not bring about marked decrease in the rate of fermentation as expected.
Soursop juice was fermented as substrate in the presence of ammonium carbonate using saccharomyces cerevisiae to determine kinetic parameters: overall rate constant; k, order of initial reaction; n, maximum rate of fermentation; V max, catalytic constant; k 2, dissociation constant for the enzyme -substrate complex; k s, the Michaelis constant; k m, and the specific ac tivity of th e enzyme. These were obtained by monitoring the rate of carbon (IV) oxide production at different time intervals. It was observed that in the first order reaction, the overall rate constant k, with respect to ammonium carbonate is, 2.23. It's also seen tha t the curves achieved from the plots of volume of carbon dioxide produced with time approached the time axis in a shorter time and the reaction was faster upon its addition. Most importantly, the maximum rate of fermentation with the substrate, 2.58x102M1min-1 and ad dition of ammonium carbonate is 2.49x102Mmin-1. The value represents the maximum velocity attainable. The maximum rate at which all the enzyme molecules were in the complex form was high and became lower upon the addition of the additive. This s uggests inhibition of the fermentation process by the additive due to decrease in the maximum activity of the enzyme. The catalytic constant, k 2, 8x10-2min-1 and the value upon addition of ammonium carbonate is, 2.0x10 -2 min-1 The dissociation constant of enzyme-substrate complexes, k s 1.64x102 and for the addition of ammonium carbonate is, 5.30x10 -1. The Michaelis constant, k m 1.64x102 M and 5.30x10 -1 for ammonium carbonate. The specific activity which is the unit of enzyme activity per gram of protein (yeast) is found to be 1x10 -1 in both. Finally, the effect was found to be uncompetitive from the extrapolated Lineweaver-Burk plots.
The poor secondary school students' academic achievement in Physics as shown in the literature over the past decades has been attributed to poor acquisition of mathematical competencies that can enable them to do well in practical Physics. The need to examine mathematical competencies as determinants of Physics achievement becomes necessary for sustainable education. The study which adopted an ex-post facto research design was carried out in Nsukka education zone of Enugu state during the 2021/2022 academic session. The sample size for the study was 388 senior secondary school I Physics students in 6 randomly sampled single-sex secondary schools. Trained research assistants used interview results to fill the mathematical competency in practical Physics questionnaire (MCPPQ) for each student. Grades spreadsheet was used to collect students' senior secondary certificate examination result in Physics. Cronbach's alpha, which yielded a value of.85 was used to measure the internal consistency reliability of MCPPQ. Beta-weight was used to answer all the research questions while Chi-square statistic was used to test the hypotheses at.05 level of significance and 425 degrees of freedom. The result of the study as perceived by the students indicated that basic practical Physics mathematical operations, graphing skills, generation of readings from equations derived from experimental setup and deductions from the graph in decreasing magnitude positively influenced Physics achievement in external examination. Male and female students' models were similar in terms of path coefficients in the model. Hence, it was recommended that Physics teachers should improve upon students' mathematical competencies in practical Physics to boost their Physics achievement.
In academic sector, they are high rate of infectious diseases like measles, diarrhea, coronavirus, monkey-pox, skin disease and genital infections, the occurrence of these infectious diseases came as a result of students' negligence in practicing of personal hygiene. Therefore, this study examined knowledge and practice of personal hygiene among secondary school students in Enugu State. Two specific purpose and research questions guided the study. Descriptive survey research design was adopted for the study. The population for the study consisted of 9900 secondary school students in Enugu State. 495 students made up the sample for this study. The researcher used simple random sampling technique. Specifically the reliability coefficients obtained from data generated with Statistical Package for Social Sciences (SPSS) using Kuder Richardson formula and Cronbach's alpha reliability for the internal consistency reliability, shows knowledge of personal hygiene (.85) and practice of personal hygiene (.79) respectively. A 22-items structured questionnaire tagged 'Knowledge and Practice of Personal Hygiene Questionnaire (KPPHQ)" was used for data collection. The data collected were analyzed using frequency, percentage, mean and standard deviation. The questionnaire was rated on 4-point scale of very great extent (VGE), great extent (GE), low extent (LE) and very low extent (VLE). The decision rule was that any item that has 50% and above is regarded as knowledgeable (K) while items below 50% is regarded as not knowledgeable (NK). For the personal hygiene, any item mean from 2.50 above is regarded as high while items mean below 2.50 is regarded as low. The findings showed that, majority of students have adequate knowledge of personal hygiene with the grand percentage of (69.8%) and low practice of personal hygiene with the grand mean of (2.0). The study conclude that: students are very knowledgeable of personal hygiene, but putting their knowledge into physical practice are seen as the major problems that most students face, which usually contribute to the risk of infectious diseases such as covid-19, genital infections, dental health challenges and diarrhea. The study recommend that students' knowledge as it regards to personal hygiene practice should always be appraised by the classroom teacher, for the purpose of motivating those ones that have low knowledge of personal hygiene and the school management should provide all the prerequisite personal hygiene materials for the facilitation of its practice.
