Statistical optimization of process parameters for improvement of phycobiliproteins (PBPs) yield using ultrasound-assisted extraction and its kinetic study.

The present study is mainly concerned for the development of an optimal ultrasound-assisted extraction (UAE) condition for phycobiliproteins (PBPs) from Oscillatoria sp. (BTA 170) using Taguchi methodology. Four process parameters viz. solid to liquid ratio, duty cycle, electrical acoustic intensity, and pH, for UAE were optimized using Taguchi methodology for enhanced PBPs extraction. The ratio of signal to noise (S/N) was used to compute the optimized condition required to attain a higher yield of PBPs, the average performance of individual parameter and corresponding interactive effects. The statistically significant parameters with their contribution were assessed using Analysis of variance (ANOVA). Results showed that duty cycle contributed the maximum influence (30.81%) on phycocyanin (PC) extraction followed by a solid liquid ratio (28.62%), pH (22.46%) and electrical acoustic intensity (18.10%). The highest contribution on the extraction of phycoerythrin (PE) was found from pH (33.16%), followed by duty cycle (31.57%), solid to liquid ratio (22.83%) and electrical acoustic intensity (12.45%). For extraction of allophycocyanin (APC), the duty cycle, solid to liquid ratio, pH and electrical acoustic intensity contributed 29.47, 29.07, 29.03, and 12.43% respectively. Results obtained from Taguchi methodology indicated that enhanced PC (94.10%), PE (95.20%) and APC (90.54%) can be achieved with solid-liquid ratio (0.2 g/ml), electrical acoustic intensity (16.99 w/cm2), duty cycle (75%), and pH 7 than the yield of PBPs obtained under unoptimized condition. In the present study, higher yield of PC (38.99%), PE (20.84%), and APC (11.93%) were attained with UAE compared to yield obtained from homogenized Oscillatoria sp. BTA 170 using 0.05 M phosphate buffer. Batch extraction data of PBPs under UAE was fitted well with the second order model. The values of second-order rate constant (k) were computed as 6.66 × 10-4, 64.09 × 10-4 and 1.49 × 10-4 L/mg/min for extraction of PC, PE and APC respectively. The PBPs exhibited significant antioxidant property and hydrogen peroxide scavenging activity, which were increased with the enhancement of PBPs concentration.

Characterization, genetic regulation and production of cyanobacterial exopolysaccharides and its applicability for heavy metal removal.

Cyanobacteria are uniquely suited for the development of sustainable bioproduction platforms but are currently underutilized due to lack of genetic tools. Exopolysaccharide (EPS) is of significant biotechnological importance due to their technological application in various industries. It has been found that most of the research works are focused on isolation and characterization of new exopolysaccharides from microbial sources. The exopolysaccharides from cyanobacteria have been poorly explored despite their original structural features associated with specific biological and physicochemical properties. However, it could increase in a near future through the use of inexpensive cyanobacterial platform as well as available information on the structural data and specific properties of these biopolymers. This review covers genetic regulation for production of exopolysaccharide, analytical strategies for their characterization, evaluation of structure property relationship and design of extraction protocol from cyanobacterial biomass. In addition applications of exopolysaccharide for removal of heavy metal from wastewater are critically reviewed.

Production of biodiesel from microalgae through biological carbon capture: a review.

Gradual increase in concentration of carbon dioxide (CO2) in the atmosphere due to the various anthropogenic interventions leading to significant alteration in the global carbon cycle has been a subject of worldwide attention and matter of potential research over the last few decades. In these alarming scenario microalgae seems to be an attractive medium for capturing the excess CO2 present in the atmosphere generated from different sources such as power plants, automobiles, volcanic eruption, decomposition of organic matters and forest fires. This captured CO2 through microalgae could be used as potential carbon source to produce lipids for the generation of biofuel for replacing petroleum-derived transport fuel without affecting the supply of food and crops. This comprehensive review strives to provide a systematic account of recent developments in the field of biological carbon capture through microalgae for its utilization towards the generation of biodiesel highlighting the significance of certain key parameters such as selection of efficient strain, microalgal metabolism, cultivation systems (open and closed) and biomass production along with the national and international biodiesel specifications and properties. The potential use of photobioreactors for biodiesel production under the influence of various factors viz., light intensity, pH, time, temperature, CO2 concentration and flow rate has been discussed. The review also provides an economic overview and future outlook on biodiesel production from microalgae.

Characterization and Optimization of Bioflocculant Exopolysaccharide Production by Cyanobacteria Nostoc sp. BTA97 and Anabaena sp. BTA990 in Culture Conditions.

Bioflocculant exopolysaccharide (EPS) production by 40 cyanobacterial strains during their photoautotrophic growth was investigated. Highest levels of EPS were produced by Nostoc sp. BTA97 and Anabaena sp. BTA990. EPS production was maximum during stationary growth phase, when nitrogenase activity was very low. Maximum EPS production occurred at pH 8.0 in the absence of any combined nitrogen source. The cyanobacterial EPS consisted of soluble protein and polysaccharide that included substantial amounts of neutral sugars and uronic acid. The EPS isolated from Anabaena sp. BTA990 and Nostoc sp. BTA97 demonstrated high flocculation capacity. There was a positive correlation between uronic acid content and flocculation activity. The flocculant bound a cationic dye, Alcian Blue, indicating it to be polyanionic. The 16S rRNA gene sequences for Nostoc sp. BTA97 and Anabaena sp. BTA990 were deposited at NCBI GenBank, and accession numbers were obtained as KJ830951 and KJ830948, respectively. The results of these experiments indicate that strains Anabaena sp. BTA990 and Nostoc sp. BTA97 are good candidates for the commercial production of EPS and might be utilized in industrial applications as an alternative to synthetic and abiotic flocculants.