Enzymatic pre-treatment of microalgae cells for enhanced extraction of proteins

Sulaiman Al-Zuhair, Salman Ashraf, Soleiman Hisaindee, Naeema Al Darmaki, Sinan Battah, Dimitri Svistunenko, Brandon Reeder, Glyn Stanway, Afeefa Chaudhary

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)

Abstract

Crude proteins and pigments were extracted from different microalgae strains, both marine and freshwater. The effectiveness of enzymatic pre-treatment prior to protein extraction was evaluated and compared to conventional techniques, including ultrasonication and high-pressure water extraction. Enzymatic pre-treatment was chosen as it could be carried out at mild shear conditions and does not subject the proteins to high temperatures, as with the ultrasonication approach. Using enzymatic pre-treatment, the extracted proteins yields of all tested microalgae strains were approximately 0.7 mg per mg of dry cell weight. These values were comparable to those achieved using a commercial lytic kit. Ultrasonication was not very effective for proteins extraction from Chlorella sp., and the extracted proteins yields did not exceed 0.4 mg per mg of dry cell weight. For other strains, similar yields were achieved by both treatment methods. The time-course effect of enzymatic incubation on the proteins extraction efficiency was more evident using laccase compared to lysozyme, which suggested that the former enzyme has a slower rate of cell disruption. The crude extracted proteins were fractionated using an ion exchange resin and were analyzed by the electrophoresis technique. They were further tested for their antioxidant activity, the highest of which was about 60% from Nannochloropsis sp. The total phenolic contents in the selected strains were also determined, with Chlorella sp. showing the highest content reaching 17 mg/g. Lysozyme was also found to enhance the extraction of pigments, with Chlorella sp. showing the highest pigments contents of 16.02, 4.59 and 5.22 mg/g of chlorophyll a, chlorophyll b and total carotenoids, respectively.

Original languageEnglish
Pages (from-to)175-185
Number of pages11
JournalEngineering in Life Sciences
Volume17
Issue number2
DOIs
Publication statusPublished - Feb 1 2017

Keywords

  • Cell disruption
  • Enzymes
  • Microalgae
  • Pigments
  • Proteins

ASJC Scopus subject areas

  • Biotechnology
  • Environmental Engineering
  • Bioengineering

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