In this study a simple protocol was developed for purifying phycocyanin (PC) from Spirulina platensis (CCC540) by using ammonium sulphate precipitation, followed by a single step chromatography by using DEAE-Cellulose-11 and acetate buffer. Precipitation with 65 % ammonium sulphate resulted in 80 % recovery of phycocyanin with purity of 1.5 (A620/A280). Thro1ugh chromatography an 80 % recovery of phycocyanin with a purity of 4.5 (A620/A280) was achieved. In SDS_PAGE analysis, the purified PC showed the presence of two subunit α (16 kD) and β (17 kD).Electronic supplementary materialThe online version of this article (doi:10.1007/s40502-014-0094-7) contains supplementary material, which is available to authorized users.

The impending danger of climate change and pollution can now be seen on the world panorama. The concentration of CO 2 , the most important Green House Gas (GHG), has reached to formidable levels. Although carbon capture and storage (CCS) methods have been largely worked upon, they are cumbersome in terms of economy and their long term environmental safety raises a concern. Alternatively, bio-sequestration of CO 2 using microalgal cell factories has emerged as a promising way of recycling CO 2 into biomass via photosynthesis which in turn could be used for the production of bioenergy and other value-added products. Despite enormous potential, the production of microalgae for low-value bulk products and bulk products such as biofuels, is heretofore, not feasible. To achieve economic viability and sustainability, major hurdles in both, the upstream and downstream processes have to be overcome. Recent technoeconomic analyses and life-cycle assessments of microalgae-based production systems have suggested that the only possible way for scaling up the production is to completely use the biomass in an integrated biorefinery setup wherein every valuable component is extracted, processed and valorized. This article provides a brief yet comprehensive review of the present carbon sequestration and utilization technologies, focusing primarily on biological CO 2 capture by microalgae in the context of bio-refinery. The paper discusses various products of microalgal biorefinery and aims to assess the opportunities, challenges and current state-of-the-art of microalgae-based CO 2 bioconversion, which are essential to the sustainability of this approach in terms of the environment as well as the economy.

Microalgae are autotrophic microorganisms having extremely high photosynthetic efficiency and are valued as rich source of lipids, hydrocarbons, and other complex oils for biodiesel besides being an invaluable source of bioethanol, biomethane, and biohydrogen. Biodiesel produced from oilseed crops such as jatropha and soy have lower yields per unit land area and threaten food security. Indeed, microalgae have higher oil yields amounting to about 40 times more oil per unit area of land in comparison to terrestrial oilseed crops such as soy and canola. Further, microalgae production does not require arable land for cultivation. Biofuel is regarded as a proven clean energy source and several entrepreneurs are attempting to commercialize this renewable source. Technology for producing and using biofuel has been known for several years and is frequently modified and upgraded. In view of this, a review is presented on microalgae as second generation biofuel. Microalgal farming for biomass production is the biggest challenge and opportunity for the biofuel industry. These are considered to be more efficient in converting solar energy into chemical energy and are amongst the most efficient photosynthetic plants on earth. Microalgae have simple cellular structure, a lipid-rich composition, and a rapid rate of reproduction. Many microalgal strains can be grown in saltwater and other harsh conditions. Some autotrophic microalgae can also be converted to heterotrophic ones to accumulate high quality oils using organic carbon. However, there are several technical challenges that need to be addressed to make microalgal biofuel profitable. The efficiency of microalgal biomass production is highly influenced by environmental conditions, e.g., light of proper intensity and wavelength, temperature, CO 2 concentration, nutrient composition, salinities and mixing conditions, and by the choice of cultivation systems: open versus closed pond systems, photobioreactors. Currently, microalgae for commercial purpose are grown mostly in open circular/elongated "raceway" ponds which generally have low yields and high production costs. However, a hybrid system combining closed photobioreactor and open pond is a better option. The biggest hurdle in commercialization of microalgal biofuel is the high cost and energy requirement for the microalgal biomass production, particularly agitation, harvesting, and drying of biomass. In order to conserve energy and reduce costs, algae are often harvested in a two-step process involving flocculation followed by centrifugation, filtration, or micro-straining to get a solid concentration. However, the major bottlenecks in algal biodiesel production within the cell can be identified and handled by adopting a system approach involving transcriptomics, proteomics, and metabolomics. Research and developments in the field of new materials and advanced designs for cultivation in closed bioreactors, use of waste water for biomass production, screening of efficient strains, high-value coproduct strategy,...

Grain legumes are an important component of sustainable agri-food systems. They establish symbiotic association with rhizobia and arbuscular mycorrhizal fungi, thus reducing the use of chemical fertilizers. Several other free-living microbial communities (PGPR—plant growth promoting rhizobacteria) residing in the soil-root interface are also known to influence biogeochemical cycles and improve legume productivity. The growth and function of these microorganisms are affected by root exudate molecules secreted in the rhizosphere region. PGPRs produce the chemicals which stimulate growth and functions of leguminous crops at different growth stages. They promote plant growth by nitrogen fixation, solubilization as well as mineralization of phosphorus, and production of phytohormone(s). The co-inoculation of PGPRs along with rhizobia has shown to enhance nodulation and symbiotic interaction. The recent molecular tools are helpful to understand and predict the establishment and function of PGPRs and plant response. In this review, we provide an overview of various growth promoting mechanisms of PGPR inoculations in the production of leguminous crops.

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