diff --git a/src/main/java/org/gcube/accounting/persistence/AccountingPersistence.java b/src/main/java/org/gcube/accounting/persistence/AccountingPersistence.java
index e2650ad..c530be0 100644
--- a/src/main/java/org/gcube/accounting/persistence/AccountingPersistence.java
+++ b/src/main/java/org/gcube/accounting/persistence/AccountingPersistence.java
@@ -16,10 +16,14 @@ import org.gcube.documentstore.records.Record;
  */
 public class AccountingPersistence {
 	
-	protected PersistenceBackend persistenceBackend;
+	protected String scope;
 	
 	protected AccountingPersistence(String scope){
-		persistenceBackend = PersistenceBackendFactory.getPersistenceBackend(scope);
+		this.scope = scope;
+	}
+
+	private PersistenceBackend getAccountingPersistence(){
+		return PersistenceBackendFactory.getPersistenceBackend(this.scope);
 	}
 	
 	/**
@@ -33,18 +37,18 @@ public class AccountingPersistence {
 	 */
 	public void account(final Record record) throws InvalidValueException {
 		try {
-			persistenceBackend.account(record);
+			getAccountingPersistence().account(record);
 		} catch (org.gcube.documentstore.exception.InvalidValueException e) {
 			throw new InvalidValueException(e);
 		}
 	}
 	
 	public void flush(long timeout, TimeUnit timeUnit) throws Exception {
-		persistenceBackend.flush(timeout, timeUnit);
+		getAccountingPersistence().flush(timeout, timeUnit);
 	}
 	
 	public void close() throws Exception{
-		persistenceBackend.close();
+		getAccountingPersistence().close();
 	}
 	
 }