Biological protein precipitation: A green process for the extraction of cucumisin from melon (Cucumis melo L. inodorus) by-products

Abstract

Cucumisin (CUC) from industrial melon by-products was separated for the first time through biological precipitation using carrageenan (CRG). This approach could represent a cost-effective and environmentally friendly process for the industries, avoiding the use of expensive equipment and toxic salts or solvents, such as butanol and ethanol. In this study, biological precipitation of proteins from melon by-products using CRG was studied and compared with conventional precipitation with ammonium sulphate. Different methods were applied for the identification and characterization of isolated proteins, including SDS-PAGE gel, FPLC and proteolytic activity assays. The isolated CUC confirmed a molecular weight of 68 kDa and showed highly stable proteolytic (PA) and milk-clotting (MCA) activities in a wide range of CaCl 2 (20-60 mM), pH (5-7) and temperatures (30-85 • C). Melon peel extract demonstrated to possess significant PA (4.24 U/mg protein) and MCA (191.50 MCU/mg protein), but such values were increased by ammonium sulphate precipitation (1.60 and 2.06-folds, respectively), and specially a noticeable increment was observed by biological precipitation with 2.11 and 17.65-folds, respectively, demonstrating the capability to be an effective strategy to isolate and purify CUC, allowing a yield of 0.17 g CUC/100 g of by-products and keeping its biological properties.

Importance of Certain Varieties of Cucurbits in Enhancing Health: A Review

“…Also, a study revealed the presence of several biologically active phytocompounds in Cucumis melo extracts obtained with various solvent systems, demonstrating the fruit's cancer-inhibiting properties, and supporting the fruit's use in future research for the treatment of various diseases [50]. The fruit is used for its juice, with thermal sterilization techniques, such as high-temperature and short-time sterilization, commonly employed to increase safety and expiration life [51]. According to study results, the peels possess proteolytic (4.24 U/mg protein) and milk-clotting (6300 One Milk-Clotting Unit/mg protein) activities, with a milk-clotting activity/proteolytic activity ratio of 1485.…”

Polyelectrolyte Precipitation: A New Green Chemistry Approach to Recover Value-Added Proteins from Different Sources in a Circular Economy Context

“…Following this subject matter, another research work was carried out for the extraction of a poorly explored enzyme from melon by-products (peels) called cucumisin with proteolytic and milk-clotting properties. The precipitation process was conducted by applying carrageenan at a lesser concentration (0.003-0.006% w/v, pH 3), obtaining better purification factors on proteolytic and milk-clotting activity (2.11-and 17.65-fold, respectively), when compared with the ammonium salt precipitation (1.60-and 2.06-fold, respectively) as well as a high recovery yield of enzymatic activity (60-80%) [62]. In summary, based on the good results and insights attributed by the application of polyelectrolyte precipitation and its favorable patent applications and developments as a measure of technological innovation, it could be suggested that this technique not only represents an eco-friendly extractive method but also a promising technology to generate new business lines and be transferred to pilot or industrial levels for the obtention of bioactive proteins with high market demands.…”

Simultaneous determination of nine tyrosine kinase inhibitors in three complex biological matrices by using high‐performance liquid chromatography–diode array detection combined with a second‐order calibration method

“…At present, the commonly used pretreatment methods include liquid‐liquid extraction, solid‐phase extraction, immunoaffinity extraction, and protein precipitation, etc. These pre‐treatment methods usually require a time‐consuming procedure, expensive reagents, poor reproducibility, and complicated operations [2–6]. Toxic reagents also have certain adverse effects on operators and the environment.…”