Selection, Characterization and Application of Bioemulsifiers Produced by certain Bacteria Isolated from Egyptian Habitats.

Abstract

In the first part of this project 59 bacterial strains were isolated from different Egyptian habitats and studied for their biosurfactant/bioemulsifier activities when were grown on one type of culture medium. In this part (the second part) 17 active strains from those of the first part were selected and studied during the second part of this research project. The 17 bacterial strains were identified down to genus as follows: Corynebacterium (5 strains), Bacillus (5 strains), Arthrobacter (3 strains), Acinetobacter (2 strains) and Pseudomonas (2 srains). The results show that strains of the Corynebacterium and Bacillus were more surface active especially strains MSA 59, MSA 53, MSA 28, and MSA 5 (124.0±6.4 – 176.7±0.0 cm2 ODA). Other strains were of moderate to weak surface active. The results also show that all of the 17 bacterial strains were able to emulsify spent motor oil and crude petroleum oil with E24 of 56.1-100% E24 (except 2 strains of 48.1-48.6 E24).

This indicates that these active strains may represent promising candidate in petroleum industries. The results of the emulsification activity 8 selected bacterial strains as affected by the addition of different vegetable oil show that used frying oil followed by corn oil were promising for obtaining high surface activities by the selected 8 strains. It was observed that the surface activities are differing from strain to strain and from oil to oil as substrates. As a result of this study Corynebacterium strains and Bacillus may be selected for further studies. Other strains are weak to moderate surface active, but at the same time they showed higher emulsification activities especially for spent motor oil. The results also that waste frying oil and nutrient broth without oil. One of the Bacillus strains (MSA 53) was of surface and emulsification activities was selected and studied for the effect of different pH values and different sodium chloride concentration of the emulsification activity (E24%). The results show that no significant variation between the different pH and the different Nacl concentration.