Process-intensified extraction of phycocyanin followed by β-carotene from Spirulina platensis using ultrasound-assisted extraction

ABSTRACT

The development of sustainable technology for the extraction of value-added products from the ecological feedstock is gaining importance. The present work focuses on the intensification of extraction of different metabolites such as phycocyanin and β carotene from microalgae (Spirulina platensis) and also presents the optimum extraction parameters using an ultrasound-assisted approach. Initially, phycocyanin was extracted from lyophilized biomass of Spirulina platensis using an ultrasound-assisted approach, and then the extract was centrifuged and the supernatant was treated by using the sugaring-out method to separate phycocyanin from chlorophyll. The remaining biomass was further used for the extraction of β-carotene using the same ultrasound-assisted approach. Various operating parameters such as amplitude, duty cycle, sonication time, and depth of horn immersed into the solution have been investigated for intensified extraction. Moreover, Taguchi design of experiments was used to evaluate the yield of β-carotene using the L₉ orthogonal array based on the effect of probe length, amplitude, duty cycle, and sonication time. On the basis of results and signal-to-noise (S/N) ratio analysis, a ranking of the parameters was performed. It can be noted here that the order of ranking was amplitude > sonication time > duty cycle > depth of horn immersing into the solution. Overall, it has been observed that maximum extraction of phycocyanin and β-carotene was 67 mg/g of dry biomass and 4.66 mg/g of dry weight, which was obtained at optimal amplitudes of 80% and 66% of the duty cycle and 0.5 cm depth of horn immersing into the solution in 4 min and 10 min, respectively. The present study clearly demonstrated that significant intensification benefits can be obtained in terms of the extraction of metabolites at optimal conditions using the ultrasound-assisted approach.

KEYWORDS:

• Phycocyanin
• β carotene
• Spirulina platensis
• ultrasonication
• sugaring-out

Acknowledgments

The authors are grateful to Dr. Ashish Mohod, Dr. Pradip Dhamole, and Dr Manisha Bagal for their valuable advice and inputs. The authors also would like to acknowledge Hash Biotech Lab, Chandigarh, India, for providing the necessary support to complete the present work.