Phycocyanin extraction in Spirulina produced using agricultural waste

© Published under licence by IOP Publishing Ltd. Phycocyanin is a pigment-protein complex synthesized by blue-green microalgae such as Arthrospira (Spirulina) platensis. This pigment is used mainly as natural colouring in food industry. Previous studies have demonstrated the potential health benefits of this natural pigment. The price of phycocyanin is a vital factor that dictates its marketability. The cost of culturing the algae, particularly from the substrate used for growth, is one of the main factors that determine the price of phycocyanin. Another important factor is the growth yield of the algae. In our research, agricultural waste such as charcoal produced from rice husk was utilized for the algae cultivation to replace the synthetic chemicals such as urea and triple superphosphate used the mineral medium. The use of this low cost substrate increases the cell concentration by 60 % during 8 days' cultivation to reach 0.39 g/l. The phycocyanin extraction was performed using water at the different biomass-to-solvent ratio and shaking rates. The phycocyanin concentration and purity (A615/A280) obtained were 1.2 g/l and 0.3. These values are 40 % and 20 % lower than the value obtained from the algae produced using the synthetic chemicals. Further purification produced the extract purity required for food grade. The biomass-solvent ratio does not significantly affect the extract purity; however, the higher shaking rate during extraction reduces the purity. This finding demonstrates the potential of using rice husk as an alternative substrate to cultivate algae for phycocyanin extraction

Food and High Value Products from Microalgae: Market Opportunities and Challenges

Microalgae are a potential source of molecules for a wide range of food and novel high-value products and have good market opportunities. They can be used in biofuels, health complements, feed, medicine and cosmetics. The development of innovative and sustainable technologies with minimum energy inputs is required for large-scale cultivation and downstream processing of lipids and hydrocarbons in order for the production to be economically viable. In addition, the viability of bioenergy production from microalgae biomass is contingent on the net energy gain of the overall process, with exhaustive utilization of algal biomass for biofuel and other co-products for feed, food, and chemicals. The energy output from the biomass as fuel has to be greater than the energy required to produce and process the algae. Microalgae produce a comprehensive variety of bioproducts such as enzymes, pigments, lipids, sugars, vitamins and sterols. Moreover, its capability to alter atmospheric CO2 into beneficial products such as lipids, carbohydrates, metabolites and proteins cannot be overstated. The key challenges appear to be high cost of operation, infrastructure and maintenance, selection of algal strains with high protein contents, dewatering and commercial scale harvesting. Optimizing the manufacture and commercialization of microalgae value products depend also on numerous factors (such as market and financial affairs). There is limitation of authentic and reliable data and statistics of microalgae market opportunities which make it difficult to assess their actual potential. Long-term research is needed to develop systems for the production of sustainable algal-based products, as sustainability is a key concern especially for food, feed and fuel