ABSTRACT

This study investigated the impact of brewery effluents on the growth parameters of two microalgae species, Monoraphidium contortum and Dimorphococcus lunatus. The microalgae were subjected to seven effluent concentrations (5%, 10%, 25%, 50%, 75%, and 100%), with a control group (0%) devoid of effluent. Growth responses were assessed spectrophotometrically at 750nm using a UV-visible spectrophotometer. Physico-chemical parameters, including pH, total dissolved solids (TDS), and conductivity, were also evaluated according to standard methods. Data analysis was done using Microsoft Excel and while ANOVA was used to determine differences between the treatments. Results indicated no significant difference in growth response between Monoraphidium contortum and Dimorphococcus lunatus (p > 0.05). Monoraphidium contortum exhibited enhanced growth at higher effluent concentrations (50%, 75%, and 100%), while Dimorphococcus lunatus thrived at concentrations of 25%, 50%, 75%, and 100%. Conversely, both species showed poorer growth at lower concentrations (10%, 5%, and 0%). Percentage inhibition analysis revealed a higher stimulatory effect for Monoraphidium contortum compared to Dimorphococcus lunatus. Algal yield peaked at 75% concentration for both species, with intermediate levels at 25% and 50%. Growth rate analysis demonstrated higher rates for Monoraphidium contortum than Dimorphococcus lunatus. Cummulative growth rate analysis suggested that Monoraphidium contortum possess a greater capacity for adaptation or resilience in the environment created by the brewery effluents.  Furthermore, results of the physicochemical studies indicated that as brewery effluent concentration increased, pH, conductivity and TDS also increased, with a decrease in Dimorphococcus lunatus where the pH decreased from 11.3 at 75% to 11.2 at 100%.  These findings provide insight into the growth of microalgae species in brewery effluents.