diff --git a/spades.wdl b/spades.wdl
index 724285d4a4b0e3ee119359faf03278a15e826b34..ce9de29cecb0b48d20faff177fc1a007e0e7c312 100644
--- a/spades.wdl
+++ b/spades.wdl
@@ -49,7 +49,7 @@ task spades {
         ${"--nanopore " + nanoporeReads } \
         ${"--tslr " + tslrContigs } \
         ${"--trusted-contigs " + trustedContigs } \
-        ${"--untrusted-contigs" + untrustedContigs } \
+        ${"--untrusted-contigs " + untrustedContigs } \
         ${true="--only-error-correction" false="" onlyErrorCorrection } \
         ${true="--only-assembler" false="" onlyAssembler } \
         ${true="--careful" false="" careful } \
diff --git a/unicycler.wdl b/unicycler.wdl
index dac048a1a8a1d21390aa79378b86c2103df27acf..f7aa36a48067bcd2f880a843d1a4aa401c7f5078 100644
--- a/unicycler.wdl
+++ b/unicycler.wdl
@@ -9,8 +9,10 @@ task unicycler {
     Int? minFastaLength
     Int? keep
     Boolean? vcf
-    Int threads
-    Int memory
+    Int? threads
+    Int? memory
+    Int finalThreads = select_first(threads, 1)
+    Int finalMemory = select_first(memory, 4)
     String? mode
     Float? minBridgeQual
     Int? linearSeqs
@@ -55,7 +57,7 @@ task unicycler {
         ${"--min_fasta_length " + minFastaLength} \
         ${"--keep " + keep } \
         ${true="--vcf" false="" vcf } \
-        ${"--threads " + threads } \
+        ${"--threads " + finalThreads } \
         ${"--mode " + mode } \
         ${"--min_bridge_qual " + minBridgeQual } \
         ${"--linear_seqs " + linearSeqs } \
@@ -94,7 +96,7 @@ task unicycler {
         File log = out + "/unicycler.log"
     }
     runtime {
-        cpu: threads
-        memory: memory
+        cpu: finalThreads
+        memory: finalMemory
     }
 }
\ No newline at end of file