Microalgal starch was harnessed to produce ethanol, a promising alternative fuel, by simultaneous saccharification and fermentation (SSF) which combined the enzymatic hydrolysis of starch to glucose and the fermentation of glucose to ethanol by Saccharomyces cerevisiae in a single step. The starch content was increased in a microalga, Chlorella sp., from 19.3% to 38.2% (w/w) by cycloheximide treatment. Crude amylase with the activity of 40 U mL⁻¹, produced by Aspergillus niger, was used to hydrolyze the microalgal starch. An SSF process was applied for the production of bioethanol using S. cerevisiae, and 0.116 g ethanol/g of algal biomass was produced. It was observed that the yield factor for ethanol production from Chlorella starch was 0.305 (g g⁻¹). A mathematical model was formulated to describe the kinetics of SSF based on considerations of the nature of the substrate and enzyme, and the substrate–enzyme–microorganism interactions. Critical experimentation was performed to conduct multiresponse nonlinear regression analysis to evaluate the model parameters regarding overall cell growth and ethanol production. The calculated values agreed well with experimental data, regarding the concentration of cells, starch, glucose and ethanol. This model can be used for rational SSF optimization and scale-up in future.

Marine algal polysaccharides (MAPs) are multifunctional biopolymers with significant potential in biomedical applications. Derived from brown, red, and green algae, key examples include alginate, agar, carrageenan, fucoidan, ulvan, and laminarin. Their structural diversity underlies a broad range of biological activities, particularly among sulfated polysaccharides, which exhibit antiviral, anticancer, anticoagulant, immunomodulatory, and antioxidant effects. Owing to their biocompatibility and tunable physicochemical properties, MAPs are also valuable in wound healing, tissue regeneration, and drug delivery. Advances in ultrasound-, microwave-, and enzyme-assisted extraction methods have enhanced yield and functionality. This review combines structural, extraction, and biomedical views on MAPs, with a focus on how molecular characteristics relate to their potential as drugs. Future work should focus on scalable green extraction, molecular-level characterization, and clinical validation to develop MAPs-based biomaterials for next-generation drug delivery, wound healing, and tissue engineering.