Abstract:
Enzymes are widely used in industries including food, textile, pharmaceutical and biofuel
due to their specificity and efficiency under mild conditions. However, their applicability
is limited by instability, short lifespan, and challenges in large- scale recovery. This study
evaluated the effect of immobilizing lipase in alginate beads on biodiesel production
using virgin coconut oil as the substrate. Lipase enzyme and alginate were extracted from
rice milling by- products and Sargassum ilicifolium, respectively. FT-IR analysis of
alginate extracted -
-O stretching), closely
matching pure sodium alginate. The Lowry assay detected the protein content of crude
rice bran lipase as 6.07 mgmL-1. Alginate beads were prepared in four different ratios of
alginate-to-crude rice bran lipase (1:0.5, 1:1, 1:1.5, 1:4) and stored at 4 °C. Hydrolytic
activity was assessed using coconut oil/PVA as a substrate, with the 1:4 ratio showed the
highest activity (0.2341 U). Biodiesel is produced through transesterification, where
triglycerides react with alcohol in the presence of a catalyst. This was evaluated against
alkali-alcohol and free crude lipase methods. Yield of biodiesel, glycerol and density
were 49.19%, 26.37%, and 0.743 kg/m³, respectively, with a higher saponification value
(111.41 mg KOH/g) and smoke point (230 °C) compared to the other methods. The use
of alginate as a polymer substrate provides a sustainable approach for enzyme reuse in
industrial applications. Future studies should focus on optimizing alginate and
purification techniques for the reusability of these beads.
