diff --git a/public/biopet-extensions/src/main/scala/nl/lumc/sasc/biopet/extensions/qiime/MergeOtuMaps.scala b/public/biopet-extensions/src/main/scala/nl/lumc/sasc/biopet/extensions/qiime/MergeOtuMaps.scala
index db9ed0f7e3c4875afcf94babe19cd686783107de..ce070ccff0b2dd7973e376344f61095ec6815e8e 100644
--- a/public/biopet-extensions/src/main/scala/nl/lumc/sasc/biopet/extensions/qiime/MergeOtuMaps.scala
+++ b/public/biopet-extensions/src/main/scala/nl/lumc/sasc/biopet/extensions/qiime/MergeOtuMaps.scala
@@ -38,7 +38,7 @@ class MergeOtuMaps(val root: Configurable) extends BiopetCommandLineFunction wit
 
   var failuresFp: Option[File] = None
 
-  override def defaultCoreMemory = 4.0
+  override def defaultCoreMemory = 8.0
 
   override def beforeGraph(): Unit = {
     super.beforeGraph()