Effects of harvesting Spirulina platensis biomass using coagulants and electrocoagulation-flotation on enzymatic hydrolysis.

This study aimed to assess the harvesting of Spirulina platensis using coagulants and electrocoagulation-flotation (ECF) and to evaluate its influence on enzymatic hydrolysis. Using nine chemical coagulants, we obtained a biomass harvesting efficiency of up to 99.5%. Using ECF, the harvesting efficiency at the aluminum and carbon electrode was 98%-99% and 33.8%-86.9%, respectively. Hydrolysis efficiency (HE) with amylases varied from 17% to 42%, and the degree of hydrolysis (DH) with proteases varied from 1.26% to 4.07%, compared with an HE of 31% and a DH of 3.57% in the centrifuged biomass. Compared to an HE of 61.75% for the centrifuged biomass, and HE of 99% and 85.46% was obtained for the biomass harvested using the aluminum and carbon electrodes. The HEs with the electrodes were better than those with the alternative methods and centrifugation; hence, with some optimization, the biomass harvested could be used for enzymatic hydrolysis.

Development of Bioactive Nanopeptide of Microalgal Origin.

The objective of this work was to produce nanoparticles containing bioactive peptides obtained by the enzymatic hydrolysis reaction of microalgal biomass. The hydrolysates were purified by vacuum filtration with membranes of different sizes and by vertical column membranes. After each step, an antioxidant activity test was conducted. The nanoparticles were developed by nanoatomization, with the size and morphology of the particles analyzed by scanning electron microscopy (SEM). The microalgae hydrolysates showed high antioxidant activity compared to non-hydrolyzed biomass. The nanoatomization of bioactive peptides caused no significant reduction in antioxidant activity, with maximum reductions of 15.0 and 17.4% by DPPH assay and 2.5 and 3.8% determined by reducing power assay for Spirulina LEB 18 and Chlorella pyrenoidosa, respectively, with no reduction in the ABTS values. Nanoparticles with sizes ranging from 14­18 nm and 72­108 were obtained for the Spirulina and Chlorella hydrolysates, respectively.