MICROALGAE

This study investigated the effects of different urea concentrations on the growth of Chlorella vulgaris and Scenedsemus, two freshwater microalgae species were analyzed under laboratory conditions. The experiment involved subjecting the microalgae to varying concentration of urea (Control, 10%, 20%, 40%, 60%, 80% and 100%). Absorbance was measured using a 721-visible Spectrophotometer at 750nm. Physicochemical parameters such as pH, turbidity, dissolved oxygen, conductivity and total dissolved solids were analyzed. Data was evaluated using descriptive statistics, two way analysis of variance and t-tests analysis and was conducted in Microsoft Excel 2010. Results revealed significant variation in the growth responses of both microalgae. Chlorella vulgaris exhibited optimal growth at 20% and 40% urea concentration with lowest growth occurring at higher concentrations. Scendesmus, on the other hand had the highest growth at 20% urea concentration with extremely low growth at higher levels. This infers that Chlorella vulgaris was more tolerant to higher concentrations of urea and ammonia toxicity than Scenedesmus. All physicochemical parameters and growth showed significant differences across concentrations of urea apart from Turbidity

A study on the effect of ampicillin on microalgae Chlorella vulgaris and Euglena viridis was carried out. The experiment was carried out for 14 days using concentration at 0mg/l (control), 10mg/l, 20mg/l, 40mg/l, 60mg/l, 80mg/l, 100mg/l of ampicillin, affected the growth of Chlorella vulgaris and Euglena viridis. Samples were analysed throughout the experiment for physiochemical parameters using standard methods. The result showed that the different concentration of ampicillin affect the growth of Chlorella vulgaris and Euglena viridis and was inhibited at 10mg/l, 20mg/l, and 40mg/l treatment. The pH value at the beginning of all the experiment for all the treatment were unstable and around 8.16 and 6.68 but increased gradually at the end of experiment across all treatment. There was significant difference in the growth of the microalgae to the ampicillin concentration

This study was carried out to assess the effect of spent engine oil on the growth of two microalgae Monoraphidium contortum and Dimorphococcus lunatus. The test algae were grown in seven concentrations of 0% (control), 5%, 10%, 25%, 50%, 75% and 100% which were set up in triplicates. The growth response was monitored every two days for 14days using a visible spectrophotometer (Model No. HV-721). The percentage inhibition, percentage yield, growth rate, and cumulative growth rate and analysis of variance (ANOVA) were calculated using Microsoft Excel software. Physicochemical parameters were also assessed including, pH, total dissolved solids and electrical conductivity using prescribed methods. The results obtained showed that both microalgae species exhibited a positive growth response to the WSF, with Monoraphidium contortum consistently demonstrating higher growth compared to Dimorphococcus lunatus across all tested WSF concentrations. Statistical analysis using ANOVA indicated no significant difference (p > 0.05) in growth response among the various WSF concentrations for both species. However, temporal differences between measurements were statistically significant (p < 0.001). Percentage inhibition analysis revealed growth stimulation at low concentrations (5%, 10%, 25%, and 50%) and inhibition at high concentrations (75% and 100%) for both species, with Monoraphidium contortum showing higher inhibitory response relative to Dimorphococcus lunatus. Algal yield was enhanced at low to high concentrations (0-75%) for Monoraphidium contortum and low to moderate concentrations (0-50%) for Dimorphococcus lunatus. Growth rate analysis consistently favored Monoraphidium contortum across all WSF concentrations tested. Cumulative growth rate analysis suggested that Dimorphococcus lunatus may be less tolerant to WSF components compared to Monoraphidium contortum. Furthermore, total dissolved solids, electrical conductivity, and pH increased significantly on termination of the experiment. Based on the findings of this study, both microalgae showed bioremediation potentials and should be further studied

This study investigated the effect of water soluble fractions of crude oil on the growth of Monoraphidium contortum and Dimorphococcus lunatus over a 14 day period. The test algae were grown in concentrations of CHU 10 nutrient media mixed with varying concentrations of WSF of crude oil (5%,10%, 25%, 50%, 75% 100%) which were prepared in triplicates. The growth response was measured using a visible spectrophotometer at two day intervals over a 14 day period. Physicochemical parameters (pH, EC, and TDS) were assessed on day 14 of the experiment and were compared to the stock concentration before exposure to the test microalgae. The results showed that there was growth stimulation for all concentrations of 0%, 5%,10%, 25%, 50%,75%, and 100% from day 0 to day 2, and a lag phase from day 2 to day 4 for 10% and 100%. The highest growth was recorded at 5% concentration on day 14
with an absorbance value of 0.035, followed closely by 100%, 50%, and 75% concentrations, while 10% WSF showed the least growth on day 14 with an absorbance value of 0.02. Statistically, the growth response of the microalgae to the WSF concentrations did not differ significantly (p > 0.005). Generally the percentage yield was higher in M.contortum compared to D.lunatus. The physicochemical properties of Dimorphococcus lunatus and onoraphidium contortum showed that when the quantity of WSF was reduced, both TDS and electrical conductivity rose. On the other hand, the pH revealed that it was somewhat more alkaline with a lower WSF concentration, suggesting acidity with a higher WSF. To summarize, Dimorphococcus lunatus exhibited a strong inhibitory reaction, and Monoraphidium contortum is better suited for bioremediation of crude oil in contaminated water.