A simple and sensitive method for the estimation of microbial lipase activity

Recently, the application of lipase enzyme as biocatalyst in the conversion of waste cooking oil (WCO) to free fatty acids and glycerol has been trending well. Therefore, the present study attempts to use WCO which is found in abundance in Malaysia as the substrate for halal microbial lipase conversion to glycerol which can be exploited in the food industry. The workability of free lipase for WCO conversion, however suffers severely due to potential denaturation of the enzyme and extended reaction time. Thus, this study embraced the immobilization method to encapsulate crude lipase extracted from Rhodococcus pyridinivorans strain UCC 0009 in gellan gum and calcium alginate, respectively and compared their ability for WCO conversion to free crude lipase. The gellan gum and calcium alginate-immobilized crude lipase evidently exhibited greater WCO conversion, demonstrating 2.18-fold and 1.61-fold enhanced lipase activity, respectively in comparison to free crude lipase. The repeated reuse of the gellan gum-immobilized crude lipase maintained reasonable lipase activity for 9 cycles, retaining an average 85 % WCO conversion for the first seven cycles and 67 % conversion in the subsequent batches. Thus, the immobilized halal lipase can be foreseen as a green substitute to chemical catalyst for WCO conversion which meets the worldwide demand for clean technologies.

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Relationship Between Total Prothrombin, Native Prothrombin and the International Normalized Ratio (INR)

Thrombosis and Haemostasis ◽

10.1055/s-0038-1656342 ◽

1992 ◽

Vol 68 (02) ◽

pp. 160-164 ◽

Cited By ~ 3

Author(s):

P J Braun ◽

K M Szewczyk

Keyword(s):

Anticoagulant Therapy ◽

Oral Anticoagulant ◽

Inverse Relationship ◽

Low Dose ◽

Oral Anticoagulant Therapy ◽

International Normalized Ratio ◽

Antigen Assay ◽

Dose Oral ◽

Anticoagulated Patients ◽

Sensitive Method

SummaryPlasma levels of total prothrombin and fully-carboxylated (native) prothrombin were compared with results of prothrombin time (PT) assays for patients undergoing oral anticoagulant therapy. Mean concentrations of total and native prothrombin in non-anticoagulated patients were 119 ± 13 µg/ml and 118 ± 22 µg/ml, respectively. In anticoagulated patients, INR values ranged as high as 9, and levels of total prothrombin and native prothrombin decreased with increasing INR to minimum values of 40 µg/ml and 5 µg/ml, respectively. Des-carboxy-prothrombin increased with INR, to a maximum of 60 µg/ml. The strongest correlation was observed between native prothrombin and the reciprocal of the INR (1/INR) (r = 0.89, slope = 122 µg/ml, n = 200). These results indicated that native prothrombin varied over a wider range and was more closely related to INR values than either total or des-carboxy-prothrombin. Levels of native prothrombin were decreased 2-fold from normal levels at INR = 2, indicating that the native prothrombin antigen assay may be a sensitive method for monitoring low-dose oral anticoagulant therapy. The inverse relationship between concentration of native prothrombin and INR may help in identification of appropriate therapeutic ranges for oral anticoagulant therapy.

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