Abstract
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Saudi Arabia heavily depends on oil production, as 33.42 % of GDP is generated from the oil sector (Saudi Arabian Monetary Agency, 2019). Due to previous fact, microorganism considers the main concern for oil biodegradation process. As a result of highly advantage of employed yeast for oil biodegradation than bacteria, this study was carried out to isolate crude oil biodegrading yeast from sediments from three points of Ras Tanura City (26°38′38″N and 50°9′33″E), eastern province, Kingdom of Saudi Arabia. Among nine yeast isolates, only three isolates selected due to remarked biodegrading activities. Based on 18S rRNA Partial gene sequence, A, B and C yeast isolates were identified and submitted as Rhodotorula ingeniosa (OL659287), Rhodotorula mucilaginosa (OL659288) and Candida parapsilosis (OL659289) with 100 % identity respectively. A isolate was superior for oil consumption (8.2 %) comparing with B and C isolates which showed 6.4 % and 5.5 % respectively. Also, A isolate reflected highest hydrocarbons derivatives consumption comparing with C isolates which showed lowest hydrocarbons derivatives consumption %. Random amplified polymorphic DNA (RAPD) and SDS-PAGE techniques were employed to evaluate genetic similarity which led to explain molecular base for varied biodegradation activity for A, B and C isolates. Interestingly, A isolate which remarked with superior biodegrading activity reflected highest genetic polymorphism. On the other hand, highly genetic similarity was corresponded to decreasing degrading activity for isolate C. positive correlation was detected between genetic polymorphism and biodegrading capability for yeast isolate.