Concentration and characterization of microalgae proteins from Chlorella pyrenoidosa

Ashish G Waghmare,Shalini S Arya,Manoj K Salve,Jean Guy Leblanc

doi:10.1186/s40643-016-0094-8

Abstract

Many methods are available for the concentration of proteins; however, most are not easily scalable due to costs, the need of specialized instruments and skilled workers or are very time-consuming. Three-phase partitioning (TPP) is a separation technique that has gained a lot of interest due to its rapid, simple and scalable use for concentration, isolation and decontamination of proteins from crude samples with high recovery yields. In the present work, the effect of various parameters of TPP was evaluated to optimize the concentration of proteins from Chlorella pyrenoidosa (CP), is green algae that increasingly being used as food supplements because of its positive impacts on human health. Chlorella pyrenoidosa was cultivated in a closed system under controlled conditions. After reaching maximum growth, the microalgae was harvested, dried and powdered. Afterwards, TPP of CP cell lysate was done to concentrate protein content. To maximize protein concentration, various parameters were optimized such as solvent (t-butanol), ammonium sulphate concentration (40 % w/v), solid load (0.75 g/20 mL), pH (6), incubation time (20 min), slurry to butanol ratio (1:1.5) and enzymatic treatment (combination of Stargen™ and Carezyme™). Also, total starch, cellulose and carbohydrate content before and after the enzymatic treatment were determined to comprehend the impact of enzymatic treatment on protein concentration. Using these optimized parameters, 78.1 % w/w protein concentration was obtained in middle protein concentrate phase. This protein concentrate was characterizedfor proximate composition, colour analysis, water holding capacity, oil-holding capacity, foaming capacity, foam stability, amino acid composition, protein quality and thermal properties. Various process parameters of TPP influence the protein concentration of middle protein concentrate phase. Enzymatically treated biomass also enhanced protein concentration in middle protein concentrate phase. Characterization of protein concentrate revealed the presence high-quality protein. Therefore, it is possible to implement TPP at an industrial scale for protein concentration.

Highlights

Many methods are available for the concentration of proteins; most are not scalable due to costs, the need of specialized instruments and skilled workers or are very time-consuming
Three-phase partitioning (TPP) of Chlorella pyrenoidosa cell lysate for protein concentration Effect of solvent on protein concentration As shown in Fig. 1, the effect of ethanol, isopropanol and t-butanol on protein concentration were studied by keeping other parameters constant such as ammonium sulphate (20 % w/v), solid load (1 g/20 mL), pH (7), incubation time (10 min) and slurry to solvent ratio (1:1)
Solvents act in TPP by increasing the buoyancy of the precipitated protein by binding to it, resulting in a middle phase that locates itself above the denser aqueous salt phase

Summary

Introduction

Many methods are available for the concentration of proteins; most are not scalable due to costs, the need of specialized instruments and skilled workers or are very time-consuming. The effect of various parameters of TPP was evaluated to optimize the concentration of proteins from Chlorella pyrenoidosa (CP), is green algae that increasingly being used as food supplements because of its positive impacts on human health. The United States, Japan, China, Taiwan and Indonesia produce over 2500 tons of dried Chlorella (Bishop and Zubeck 2012) because it is considered a good source of nutrients and a functional food due to its positive health effects (Gao 1998; Richmond 1990). Since proteins from Chlorella can act as an animal protein replacement, its use can have a positive impact on the environment (Jones 2016)

Methods

Results

Conclusion