Purification and Characterization of Alkaline-Thermostable Protease Enzyme from Pitaya (Hylocereus polyrhizus) Waste: A Potential Low Cost of the Enzyme

Abstract

The thermoalkaline protease enzyme from pitaya (Hylocereus polyrhizus) waste was purified by a factor of 221.2 with 71.3% recovery using ammonium sulphate precipitation, gel filtration, and cation exchange chromatography. Gel filtration chromatography together with sodium dodecyl sulphate gel electrophoresis (SDS-PAGE) revealed that the enzyme is monomeric with a molecular weight of 26.7 kDa. The apparent K m and V max of the protease were 2.8 mg/mL and 31.20 u/min, respectively. The optimum pH and temperature were 8.0 and 70°C. The enzyme was highly active and stable over a wide pH range (from pH 3.0 to pH 11.0 with the optimum activity at pH 8.0). The protease has broad specificity toward azocasein, casein, hemoglobin, and gelatine. Activity of the enzyme was inhibited by Fe2+ and Zn2+, while protease activity was increased in the presence of Ca2+ and Mg2+ and Cu2+ by factors of 125%, 110%, and 105%, respectively. The alkaline protease showed extreme stability toward surfactants and oxidizing agent. The purified protease exhibited extreme stability in the presence of organic solvents and inhibitors. In addition, the enzyme was relativity stable toward organic solvents and chelating agents, such as ethylenediaminetetraacetic acid (EDTA). The enzyme, derived from pitaya peel, possesses unique characteristics and could be used in various industrial and biotechnological applications.

Smoke-Free Homes and Home Exposure to Secondhand Smoke in Shanghai, China

“…This study confirmed that having a smoke-free home policy was negatively associated with exposure to SHS in the home, which is consistent with other studies [ 18 , 19 , 20 ]. Restrictions were more common when there were no smokers in the home and when there were children present [ 14 , 21 ] especially among children less than 5 years old [ 10 ]. It is surprising that having children less than 18 was positively associated with exposure to SHS in the home, which indicates that adolescents may be seriously exposed to SHS.…”

“…It is surprising that having children less than 18 was positively associated with exposure to SHS in the home, which indicates that adolescents may be seriously exposed to SHS. Other research has shown that having children less than 5 years of age was a correlate of having a smoke-free home policy while having children under 18 years old was not [ 10 ]. In addition, studies have shown that pregnancy and giving birth may serve as impetuses to establishing a smoke-free home [ 22 , 23 ].…”

“…Participants were asked, “Which statement best describes the rules about smoking inside your home? This does not include decks, garages, or porches” A complete smoke-free home was defined as “Smoking is not allowed anywhere inside your home” [ 10 ]. A partial policy was defined as “Smoking is allowed in some places or at some times.” For those participants with a complete smoke-free home policy, enforcement of such rules in six situations was assessed (listed in Table 2 ).…”

Structural and biochemical characterization of a novel thermophilic Coh01147 protease

“…Furthermore, MD simulations at 100˚C confirmed this result. This high degree of thermal stability may be beneficial in many industrial processes, for example, to decrease the risk of contamination at high temperatures and the cost of external cooling [50]. Concerning the influence of pH, protease 1147 shows approximately 80% and 50% of relative activity in pH values of 5 and 9, respectively, with good stability after 3 h of incubation at 60˚C.…”

Extraction and purification of a highly thermostable alkaline caseinolytic protease from wastes Penaeus vannamei suitable for food and detergent industries

“…It should be mentioned that thermostability of the enzyme is one of the good characteristics of the protease. In addition, thermostable enzyme can decrease the risk of contaminants at high temperature in industries and also cost of external cooling and the increased substrate solubility, allowing for higher concentrations of low solubility materials and a lower viscosity of liquids and it may also be useful in mixing (Amid, ABD Manap, & Zohdi, 2014). They can also be used to study enzyme behavior under conditions that would denature most enzymes, since enzymes resistant to heat are also, at room temperature, resistant to organic solvents, chaotropic agents, and proteolysis.…”