Application and characterization of crude fungal lipases used to degrade fat and oil wastes.

Aspergillus niger MH078571.1 and A. niger MH079049.1 were identified previously as the two highest Aspergillus niger strains producing lipase. Biochemical characterizations of lipase activity and stability for these two strains were examined and revealed that the optimal temperature is 45 °C at pH 8for A. niger MH078571.1 and 55 °C for MH079049.1. The lipase production of both strains was studied on medium contains waste oil, as a cheap source to reduce the industrial cost, showed that the optimal incubation period for the enzyme production is 3 days. Moreover, an experiment on lipase activates in organic solvents demonstrated that 50% of acetone is the best solvent for the two strains. In the presence of surfactants, 0.1% of tween 80 surfactant showed the best lipase activities. Furthermore, Mg2+ and Zn2+ ions enhanced the lipase activity of A. niger MH078571.1, while Na2+ and Cu2+ enhanced the enzyme activity of A. niger MH079049.1. Lipase activity was also tested for industrial applications such as integrating it with different detergents. Maximum lipase activity was obtained with 1% of Omo as a powder detergent for both strains. In liquid detergent, 0.1% of Fairy showed maximum lipase activity in A. niger MH078571.1, while the lipase in A. niger MH079049.1 was more effective in 1% of Lux. Moreover, the degradation of natural animal fat with crude enzyme was tested using chicken and sheep fats. The results showed that more than 90% of fats degraded after 5 days of the incubation period.

Evaluating clinical placements in Saudi Arabia with the CLES+T scale.

The clinical learning environment and supervision (CLES) tool has been enhanced with an additional sub-scale for measuring the quality of nurse teacher's involvement to form the CLES + T scale. It has been widely used in many countries to evaluate clinical placements. Here we report data from Saudi Arabia. The CLES + T was employed to measure satisfaction among student nurses concerning their clinical learning environment. Linear regression was used to determine relationships of various variables to the outcomes of total CLES + T score and those of its subscales. Students were generally satisfied with their placements. For female students the number of visits of the nurse tutor was positively associated with most subscales and with the total score. For males, who had fewer visits from a nurse tutor, there was no such association. Nurse tutor visits are positive in terms of clinical placement evaluation by female student nurses. Saudi nursing students are generally similar to students in other international studies in terms of their appraisal of clinical placements.