Evaluation of Banana Stem Ash Extract as a Low- Cost Culture Medium on the Growth and Pigmentation of Spirulina platensis

Aquaculture diets and the health food sector can benefit from Spirulina platensis as a source of vital nutrients. The commonly used Kosaric medium (KM) for S. platensis culture is expensive and not widely accessible. Thus, the present study aimed to explore the use of banana stem ash extract (BSAE) as an alternative nutrient source and its impact on S. platensis growth and pigmentation. An 18-day experiment was conducted with five treatments, including control with KM (T1) and various BSAE concentrations with and without micronutrients (T2-T5). On the 15th day of the exponential phase, the control treatment (T1) exhibited significantly higher biomass concentration (1.29± 0.11g/ L) and specific growth rate (0.570μ/ day), along with higher optical density (0.87± 0.01) and chlorophyll a content (8.74± 0.06mg/ L). However, comparable results to the control were achieved in 0.5g/ L BSAE with 0.5ml micronutrient (T3) and 1.0g/ L BSAE with 0.5ml micronutrient (T5), in terms of biomass concentration, specific growth rate, and optical density. Chlorophyll a content (8.33± 0.02mg/ L) in 1.0g/ L BSAE with 0.5mL micronutrient was better than 0.5g/ L BSAE with 0.5ml micronutrient (7.75± 0.01mg/ L). Micronutrient supplementation was crucial in the BSAE medium. Both 0.5g/ L and 1.0g /L BSAE with 0.5ml micronutrient supplementation yielded comparable results to KM, suggesting their suitability as cost-effective alternatives for S. platensis culture without compromising growth performance and pigmentation.