Extraction of phycobiliproteins (R-phycoerythrin, R-PE and R-phycocyanin, R-PC) from macro-algae is difficult due to the presence of large polysaccharides (agar, cellulose etc.) present in the cell wall which offer major hindrance for cell disruption. The present study is aimed at developing most suitable methodology for the primary extraction of R-PE and R-PC from marine macro-algae, Gelidium pusillum(Stackhouse) Le Jolis. Such extraction of phycobiliproteins by using ultrasonication and other conventional methods such as maceration, maceration in presence of liquid nitrogen, homogenization, and freezing and thawing (alone and in combinations) is reported for the first time. Standardization of ultrasonication for different parameters such as ultrasonication amplitude (60, 90 and 120µm) and ultrasonication time (1, 2, 4, 6, 8 and 10mins) at different temperatures (30, 35 and 40°C) was carried out. Kinetic parameters were estimated for extraction of phycobiliproteins by ultrasonication based on second order mass transfer kinetics. Based on calorimetric measurements, power, ultrasound intensity and acoustic power density were estimated to be 41.97W, 14.81W/cm² and 0.419W/cm³, respectively. Synergistic effect of ultrasonication was observed when employed in combination with other conventional primary extraction methods. Homogenization in combination with ultrasonication resulted in an enhancement in efficiency by 9.3% over homogenization alone. Similarly, maceration in combination with ultrasonication resulted in an enhancement in efficiency by 31% over maceration alone. Among all the methods employed, maceration in combination with ultrasonication resulted in the highest extraction efficiency of 77 and 93% for R-PE and R-PC, respectively followed by homogenization in combination with ultrasonication (69.6% for R-PE and 74.1% for R-PC). HPLC analysis was carried out in order to ensure that R-PE was present in the extract and remained intact even after processing. Microscopic studies indicated a clear relation between the extraction efficiency of phycobiliproteins and degree of cell disruption in a given primary extraction method. These combination methods were found to be effective for extraction of phycobiliproteins from rigid biomass of Gelidium pusillum macro-algae and can be employed for downstream processing of biomolecules also from other macro-algae.

The objective of the present work was to encapsulate yeast using different carrier materials and examine their efficacy in retaining viability of cells after spray drying. Slurry containing yeast cells along with known amount of carrier material (maltodextrin, corn starch, gum arabic, acacia gum, polyethylene glycol 8000, β-cyclodextrin, and skimmed milk powder, one at a time) was added and served as feed. Among these carrier materials attempted, corn starch and maltodextrin showed the best results with respect to powder yield (59%, w/w) and cell survival (80.5%), respectively. However, considering both survival and powder yield (67 and 59% w/w, respectively), corn starch was observed to be the most suitable carrier material.

The coconut residual fiber (CRF) is the major byproduct obtained during production of virgin coconut oil. Its application as a biosorbent for adsorption of Congo red was investigated. The CRF was subjected to different pretreatments, namely, pressure cooking, hexane treatment, acid treatment and their combinations. The pretreatment of CRF with the combination of hexane, acid, and pressure cooking resulted in the highest degree of adsorption. The equilibrium data were analyzed and found to fit best to both Langmuir and Freundlich isotherms. Thermodynamic parameters such as standard free energy (ΔG⁰ kJ mol⁻¹), standard enthalpy (ΔH⁰, kJ mol⁻¹) and standard entropy (ΔS⁰, kJ mol⁻¹ K⁻¹) of the systems were calculated by using the Langmuir constant. The ΔG⁰, ΔH⁰ and ΔS⁰ were found to be 16.51 kJ mol⁻¹, −19.39 kJ mol⁻¹ and −0.12 kJ mol⁻¹ K⁻¹, respectively, at 300 K. These thermodynamic parameters suggest the present adsorption process to be non-spontaneous and exothermic. The adsorption process was observed to follow pseudo-second-order kinetics. The results suggest that CRF has potential to be a biosorbent for the removal of hazardous material (Congo red dye) with a maximum adsorption capacity of 128.94 mg g⁻¹ at 300 K.