A simple method for purification of bromelain in a thermosensitive triblock copolymer-based protection system and recycling of phase components

Green and sustainable extraction of phycocyanin from Spirulina platensis by temperature-sensitive polymer-based aqueous two-phase system and mechanism study

In this study, a sustainable and environmentally friendly method was developed for the enrichment and purification of phycocyanin from Spirulina platensis. This was achieved by utilizing a temperature-sensitive polymer, Pluronic F68, in an aqueous two-phase solvent system. The phase behavior of the temperature-sensitive polymer-based biphasic system was evaluated. The extraction conditions were optimized by both single-factor experiments and response surface methodology. Under the optimal conditions, the upper polymer-rich phase was recycled for sustainable phycocyanin extraction, resulting in a grade of 3.23 during the third extraction cycle. Pluronic F68 could be efficiently recovered and reused during the extraction process. The interaction mechanism between Pluronic F68 and phycocyanin was systematically studied using FT-IR and fluorescence analysis. This was further complemented by static and dynamic calculation of molecular motion through molecular docking and molecular dynamics simulation, indicating that hydrophobic segment of Pluronic F68 played a key role in the binding process with phycocyanin.

Isolation of Proteolytic Enzyme from Pineapple Crown

The pineapple waste from the pineapple industry has contributed to an increase in waste in Malaysia and worldwide every year. A major type of endopeptidase enzymes found in pineapple is fruit bromelain, stem bromelain, ananain, and comasain. This study aims to extract and purify protease from the crown of MD2 pineapple. Protease was extracted and purified using anion exchange chromatography, gel filtration, and desalting before being identified using liquid chromatography-mass spectrometry (LC-MS). Proteolytic activity was determined using the well diffusion method and Casein Digestion Unit. In the present study, the proteolytic assay showed that 1 kg crown of MD2 cultivar produced an activity of 126.0 ± 3.86 U/ml, a specific activity of 3937.50 U/mg. In the present study, the proteolytic assay showed that 1 kg crown of MD2 cultivar produced an activity of 126.0 ± 3.86 U/mL, a specific activity of 3937.50 U/mg and the total activity of 3.94 × 109 U. The molecular weight of the purified enzyme was in the range of 25 to 35 kDa under the optimum condition of pH 7 and 37°C. Purification of the extract yielded a band at the molecular weight of 20–25 kDa at the optimum pH of 3 and 9 at 60°C. From LC-MS analysis, the purified enzyme from the crown extract was similar to ananain under accession number A0A199VSS3 (according to Uniprot). It had five unique peptides and covered 97/356 amino acids (44.9% coverage). The ananain (EC 3.4.22.31) is classified in the subfamilies of cysteine protease C1A (clan CA, family C1), a peptidase family related to papain. In conclusion, protease was extracted and identified as an ananain-like protease from the crown.

Comparative modelling studies of fruit bromelain using molecular dynamics simulation

Fruit bromelain is a cysteine protease accumulated in pineapple fruits. This proteolytic enzyme has received high demand for industrial and therapeutic applications. In this study, fruit bromelain sequences QIM61759, QIM61760 and QIM61761 were retrieved from the National Center for Biotechnology Information (NCBI) Genbank Database. The tertiary structure of fruit bromelain QIM61759, QIM61760 and QIM61761 was generated by using MODELLER. The result revealed that the local stereochemical quality of the generated models was improved by using multiple templates during modelling process. Moreover, by comparing with the available papain model, structural analysis provides an insight on how pro-peptide functions as a scaffold in fruit bromelain folding and contributing to inactivation of mature protein. The structural analysis also disclosed the similarities and differences between these models. Lastly, thermal stability of fruit bromelain was studied. Molecular dynamics simulation of fruit bromelain structures at several selected temperatures demonstrated how fruit bromelain responds to elevation of temperature.