Title : Low-frequency ultrasonication as a dual-purpose strategy for biomass and macromolecule enhancement in Chlorella sp.
Abstract:
Efficient enhancement of macromolecular yields is pivotal for the economic viability of microalgae-based biofuel production. In this study, we investigate the dual application of ultrasonication, as both a stimulatory treatment for live Chlorella sp. cultures and a downstream extraction aid. The work focuses on optimizing ultrasonication parameters, particularly duration and frequency, to promote intracellular accumulation of key macromolecules and improve biomass productivity. Low-frequency ultrasonication (50 Hz) applied for short durations demonstrated a pronounced stimulatory effect, leading to a 1.40-fold increase in lipid content and a 1.60-fold increase in carbohydrate accumulation compared to untreated controls. Additionally, chlorophyll content and overall biomass productivity were also elevated. To elucidate the physiological responses underlying these enhancements, oxidative stress and antioxidant markers, including malondialdehyde (MDA), superoxide dismutase (SOD), total phenolic content (TPC), and total antioxidant activity (TAA) were quantified. These assays indicate that mild ultrasonication stress modulates cellular redox balance, thereby promoting metabolic reprogramming toward macromolecular synthesis. Collectively, these findings highlight the potential of short-duration, low-frequency ultrasonication as a cost-effective, dual-purpose strategy for simultaneous stimulation and extraction of high-value biomolecules, advancing sustainable microalgal biofuel production.
