Isolation Of Bacterial Strains From Compost Teas And Screening Of Their PGPR Properties

The beneficial effect of compost and compost tea on plant growth and protection is mainly associated with the microbial diversity and the presence of bacteria with Plant Growth Promoting effect. PGPR are considered as eco-friendly bio-fertilizers that may reduce the use of chemical pesticides and fertilizers. Three Composts (AT, A10 and A30) were previously prepared from industrial wastes (olive mill wastewater, olive pomace, coffee ground and phosphogypsum). In the present study we isolated three bacterial strains from the compost teas. The phylogenetic identification of these bacterial strains (B.AT, B.A10 and B.A30) showed that they were affiliated with Serratia plymuthica (B.AT), Serratia grimesii (B.A10) and Achromobacter piechaudii (B.A30) species. A characterization of the PGPR traits of these three bacteria was carried out in vitro (Siderophore, Exopolysaccharides, IAA production…) and the study of their effect on potato plants growth, yields and tuber quality was studied under field culture conditions.