CHARACTERIZATION OF BIOFILM FORMING MICROORGANISMS INVOLVED IN WELL CLOGGING AT THE ARAVA VALLEY

Well clogging and fouling is mainly caused by different microorganisms that form a three dimensional organic layer called biofilm. Biofilms are characterized by dense microbial cell layers that are tied by a polymeric network consisting of different organic components such as polysaccharides, structural proteins and fats. To date, chemical and physical means are used in order to demolish the biofilm and the clogging layers. These methods are inefficient, highly expensive and do not prevent the regrowth of biofilm and the clogging. In order to provide better understanding for well clogging process, characterization of the bacterial populations affecting biofilm formation is needed. Biofilm growth was examined in the water wells of "Mekorot" in the Arava valley. The study was carried out using bacterial isolates from clogged versus unclogged wells. This allowed the examination of which bacteria are responsible for biofilm formation. The bacteria biofilm formation capabilities were then examined. Nine of the 200 bacteria isolated from the drilling sites were discovered as strong biofilm creators. Those bacteria produced at least 50% of biofouling in comparison to known bacteria biofilm producers such as Acinetobacter baumannii. The most common bacteria that were isolated from "Mekorot" drilling sites belong to Rhizobiaceae family and Pseudomonadaceae family, two families that were discovered as strong biofilm forming bacteria in our assays. Next generation sequencing was done on the biofilm scraped from different drilling wells and on coupons that were inserted into different wells for a period of 14 months. All the sequencing were analyzed using Qiime software and were compared in order to understand which bacteria are responsible for initial settlement and the different stages in biofilm formation.