diff --git a/pkg/obiapat/apat.h b/pkg/obiapat/apat.h
index c536523..5916459 100644
--- a/pkg/obiapat/apat.h
+++ b/pkg/obiapat/apat.h
@@ -106,7 +106,6 @@ typedef struct {                        /* sequence             */
     int32_t   datsiz;                   /* data buffer size     */
     int32_t   circular;
     uint8_t   *data;                    /* data buffer          */
-    char      *cseq;                    /* sequence buffer      */
     StackiPtr hitpos[MAX_PATTERN];      /* stack of hit pos.    */
     StackiPtr hiterr[MAX_PATTERN];      /* stack of errors      */
 } Seq, *SeqPtr;
diff --git a/pkg/obiapat/obiapat.c b/pkg/obiapat/obiapat.c
index 85f0c55..38b9f56 100644
--- a/pkg/obiapat/obiapat.c
+++ b/pkg/obiapat/obiapat.c
@@ -6,7 +6,7 @@
 
 #include "obiapat.h"
 
-static void EncodeSequence(SeqPtr seq);
+static void EncodeSequence(SeqPtr seq, const char *in);
 static void UpperSequence(char *seq);
 
 /*
@@ -142,64 +142,6 @@ char *ecoComplementPattern(char *nucAcSeq)
     return reverseSequence(LXBioSeqComplement(nucAcSeq),1);
 }
 
-char *ecoComplementSequence(char *nucAcSeq)
-{
-    return reverseSequence(LXBioSeqComplement(nucAcSeq),0);
-}
-
-
-char *getSubSequence(char* nucAcSeq,int32_t begin,int32_t end, 
-					int *errno, char **errmsg)
-/*
-   extract subsequence from nucAcSeq [begin,end[
-*/
-{
-	static char *buffer  = NULL;
-	static int32_t buffSize= 0;
-	int32_t length;
-	
-	if (begin < end)
-	{
-		length = end - begin;
-		
-		if (length >= buffSize)
-		{
-			buffSize = length+1;
-			if (buffer)
-				buffer=ECOREALLOC(buffer,buffSize,
-						   	      "Error in reallocating sub sequence buffer",errno,errmsg);
-			else
-				buffer=ECOMALLOC(buffSize,
-				          		 "Error in allocating sub sequence buffer",errno,errmsg);
-				
-		}
-		
-		strncpy(buffer,nucAcSeq + begin,length);
-		buffer[length]=0;
-	}
-	else
-	{
-		length = end + strlen(nucAcSeq) - begin;
-		
-		if (length >= buffSize)
-		{
-			buffSize = length+1;
-			if (buffer)
-				buffer=ECOREALLOC(buffer,buffSize,
-						   	      "Error in reallocating sub sequence buffer",errno,errmsg);
-			else
-				buffer=ECOMALLOC(buffSize,
-				          		 "Error in allocating sub sequence buffer",errno,errmsg);
-				
-		}
-		strncpy(buffer,nucAcSeq+begin,length - end);
-		strncpy(buffer+(length-end),nucAcSeq ,end);
-		buffer[length]=0;
-	}
-	
-	return buffer;
-}
-
 
 /* -------------------------------------------- */
 /* uppercase sequence                           */
@@ -229,29 +171,27 @@ void UpperSequence(char *seq)
 /* -------------------------------------------- */
 
 #define IS_UPPER(c) (((c) >= 'A') && ((c) <= 'Z'))
+#define IS_LOWER(c) (((c) >= 'a') && ((c) <= 'z'))
 
 
 
-void EncodeSequence(SeqPtr seq)
+void EncodeSequence(SeqPtr seq, const char *in)
 {
         int   i;
         uint8_t *data;
-        char  *cseq;
+        const char  *cseq;
 		char nuc;
 
         data = seq->data;
-        cseq = seq->cseq;
 
-        while (*cseq) {
-			nuc = *cseq & (~32);
-            *data = (IS_UPPER(nuc) ? nuc - 'A' : 0x0);
-            data++;
-            cseq++;
+		for (i=0,cseq=in; i < seq->seqlen; i++,cseq++,data++) {
+			nuc = *cseq;
+            *data = (IS_LOWER(nuc) ? nuc - 'a' : 0x0);
         }
-        
-        for (i=0,cseq=seq->cseq;i < seq->circular; i++,cseq++,data++) {
-			nuc = *cseq & (~32);
-            *data = (IS_UPPER(nuc) ? nuc - 'A' : 0x0);
+
+        for (i=0,cseq=in; i < seq->circular; i++,cseq++,data++) {
+			nuc = *cseq;
+            *data = (IS_LOWER(nuc) ? nuc - 'a' : 0x0);
 		}
 
         for (i = 0 ; i < MAX_PATTERN ; i++)
@@ -266,6 +206,7 @@ SeqPtr new_apatseq(const char *in,int32_t circular, int32_t seqlen,
                     SeqPtr out, 
 					int *errno, char **errmsg)
 {
+		// fprintf(stderr,">>>>>>>> new_apatseq\n");
         int    i;
 
 		if (circular != 0) circular=MAX_PAT_LEN;
@@ -287,28 +228,26 @@ SeqPtr new_apatseq(const char *in,int32_t circular, int32_t seqlen,
 		}
 
 		
-		out->seqsiz = out->seqlen = seqlen;
-		out->circular = circular;
 		
 		if (!out->data)
 		{
-			out->data = ECOMALLOC((out->seqlen+circular) *sizeof(uint8_t),
+			out->data = ECOMALLOC((seqlen+circular) *sizeof(uint8_t),
 		    	     			  "Error in Allocation of a new Seq data member",
 								   errno,errmsg);    
-		   	out->datsiz=  out->seqlen+circular;
+		   	out->datsiz=  seqlen+circular;
 		}
-		else if ((out->seqlen +circular) >= out->datsiz)
+		else if ((seqlen +circular) >= out->datsiz)
 		{
-			out->data = ECOREALLOC(out->data,(out->seqlen+circular) *sizeof(uint8_t),
+			out->data = ECOREALLOC(out->data,(seqlen+circular) *sizeof(uint8_t),
 			                      "Error during Seq data buffer realloc",
 								  errno,errmsg);
-		   	out->datsiz=  out->seqlen+circular;			                      
+		   	out->datsiz=  seqlen+circular;
 		}
-
-		out->cseq = (char *)in;
 		
-		EncodeSequence(out);
-
+		out->circular = circular;
+		out->seqlen = seqlen;
+		EncodeSequence(out,in);
+		// fprintf(stderr,">>>>>>>> Encodage ok\n");
         return out;
 }
 
diff --git a/pkg/obiapat/pattern.go b/pkg/obiapat/pattern.go
index 5f86ab1..6016d93 100644
--- a/pkg/obiapat/pattern.go
+++ b/pkg/obiapat/pattern.go
@@ -27,6 +27,7 @@ var _AllocatedApaPattern = 0
 // Apat algorithm functions and methods
 type _ApatPattern struct {
 	pointer *C.Pattern
+	pattern string
 }
 
 type ApatPattern struct {
@@ -37,6 +38,7 @@ type ApatPattern struct {
 // Apat algorithm functions and methods
 type _ApatSequence struct {
 	pointer *C.Seq
+	reference *obiseq.BioSequence
 }
 
 type ApatSequence struct {
@@ -88,7 +90,8 @@ func MakeApatPattern(pattern string, errormax int, allowsIndel bool) (ApatPatter
 		return NilApatPattern, errors.New(message)
 	}
 
-	ap := _ApatPattern{apc}
+
+	ap := _ApatPattern{apc,pattern}
 
 	runtime.SetFinalizer(&ap, func(p *_ApatPattern) {
 		// log.Printf("Finaliser called on %s\n", C.GoString(p.pointer.cpat))
@@ -111,8 +114,8 @@ func (pattern ApatPattern) ReverseComplement() (ApatPattern, error) {
 		C.free(unsafe.Pointer(errmsg))
 		return ApatPattern{nil}, errors.New(message)
 	}
-
-	ap := _ApatPattern{apc}
+	spat := C.GoString(apc.cpat)
+	ap := _ApatPattern{apc,spat}
 
 	runtime.SetFinalizer(&ap, func(p *_ApatPattern) {
 		// log.Printf("Finaliser called on %s\n", C.GoString(p.pointer.cpat))
@@ -124,7 +127,8 @@ func (pattern ApatPattern) ReverseComplement() (ApatPattern, error) {
 
 // String method casts the ApatPattern to a Go String.
 func (pattern ApatPattern) String() string {
-	return C.GoString(pattern.pointer.pointer.cpat)
+	return pattern.pointer.pattern
+	//return C.GoString(pattern.pointer.pointer.cpat)
 }
 
 // Len method returns the length of the matched pattern.
@@ -166,7 +170,6 @@ func (pattern ApatPattern) Print() {
 func MakeApatSequence(sequence *obiseq.BioSequence, circular bool, recycle ...ApatSequence) (ApatSequence, error) {
 	var errno C.int32_t
 	var errmsg *C.char
-	var p unsafe.Pointer
 	seqlen := sequence.Len()
 
 	ic := 0
@@ -178,33 +181,14 @@ func MakeApatSequence(sequence *obiseq.BioSequence, circular bool, recycle ...Ap
 
 	if len(recycle) > 0 {
 		out = recycle[0].pointer.pointer
-		if (int(out.seqlen) < seqlen || int(out.seqlen) > 5*seqlen) && out.cseq != nil {
-			C.free(unsafe.Pointer(out.cseq))
-			out.cseq = nil
-		}
 	} else {
 		out = nil
 	}
 
-	if out == nil || out.cseq == nil {
-
-		p = C.malloc(C.size_t(seqlen) + 1)
-		// if p != nil {
-		// 	// atomic.AddInt64(&_AllocatedApaSequences, 1)
-		// }
-	} else {
-		p = unsafe.Pointer(out.cseq)
-	}
-
-	if p == nil {
-		log.Panicln("Cannot allocate memory chunk for Cseq Apat sequecence")
-	}
 
 	// copy the data into the buffer, by converting it to a Go array
-	cBuf := (*[1 << 31]byte)(p)
-	copy(cBuf[:], sequence.Sequence())
-	cBuf[sequence.Len()] = 0
-
+	p := unsafe.Pointer(unsafe.SliceData(sequence.Sequence()))
+	
 	pseqc := C.new_apatseq((*C.char)(p), C.int32_t(ic), C.int32_t(seqlen),
 		(*C.Seq)(out),
 		&errno, &errmsg)
@@ -221,19 +205,14 @@ func MakeApatSequence(sequence *obiseq.BioSequence, circular bool, recycle ...Ap
 
 	if out == nil {
 		// log.Printf("Make ApatSeq called on %p -> %p\n", out, pseqc)
-		seq := _ApatSequence{pointer: pseqc}
+		seq := _ApatSequence{pointer: pseqc,reference: sequence}
 
 		runtime.SetFinalizer(&seq, func(apat_p *_ApatSequence) {
 			var errno C.int32_t
 			var errmsg *C.char
-			// log.Printf("Finaliser called on %p\n", apat_p.pointer)
+			log.Debugf("Finaliser called on %p\n", apat_p.pointer)
 
 			if apat_p != nil && apat_p.pointer != nil {
-				if apat_p.pointer.cseq != nil {
-					C.free(unsafe.Pointer(apat_p.pointer.cseq))
-					apat_p.pointer.cseq = nil
-					// atomic.AddInt64(&_AllocatedApaSequences, -1)
-				}
 				C.delete_apatseq(apat_p.pointer, &errno, &errmsg)
 			}
 		})
@@ -242,6 +221,7 @@ func MakeApatSequence(sequence *obiseq.BioSequence, circular bool, recycle ...Ap
 	}
 
 	recycle[0].pointer.pointer = pseqc
+	recycle[0].pointer.reference = sequence
 
 	//log.Println(C.GoString(pseq.cseq))
 
@@ -259,16 +239,9 @@ func (sequence ApatSequence) Free() {
 	var errno C.int32_t
 	var errmsg *C.char
 
-	// log.Printf("Free called on %p\n", sequence.pointer.pointer)
+	log.Debugf("Free called on %p\n", sequence.pointer.pointer)
 
 	if sequence.pointer != nil && sequence.pointer.pointer != nil {
-
-		if sequence.pointer.pointer.cseq != nil {
-			C.free(unsafe.Pointer(sequence.pointer.pointer.cseq))
-			sequence.pointer.pointer.cseq = nil
-			// atomic.AddInt64(&_AllocatedApaSequences, -1)
-		}
-
 		C.delete_apatseq(sequence.pointer.pointer,
 			&errno, &errmsg)
 
@@ -315,11 +288,11 @@ func (pattern ApatPattern) FindAllIndex(sequence ApatSequence, begin, length int
 	for i := 0; i < nhits; i++ {
 		start := int(stktmp[i])
 		err := int(errtmp[i])
-		log.Debugln(C.GoString(pattern.pointer.pointer.cpat), start, err)
+		//log.Debugln(C.GoString(pattern.pointer.pointer.cpat), start, err)
 		loc = append(loc, [3]int{start, start + patlen, err})
 	}
 
-	log.Debugln("------------")
+	//log.Debugln("------------")
 	return loc
 }
 
@@ -359,16 +332,17 @@ func (pattern ApatPattern) BestMatch(sequence ApatSequence, begin, length int) (
 	end = obiutils.MinInt(end, sequence.Len())
 
 	cpattern := (*[1 << 30]byte)(unsafe.Pointer(pattern.pointer.pointer.cpat))
-	cseq := (*[1 << 30]byte)(unsafe.Pointer(sequence.pointer.pointer.cseq))
+    frg := sequence.pointer.reference.Sequence()[start:end]
+
 
 	log.Debugln(
-		string((*cseq)[start:end]),
+		string(frg),
 		string((*cpattern)[0:int(pattern.pointer.pointer.patlen)]),
 		best[0], nerr, int(pattern.pointer.pointer.patlen),
 		sequence.Len(), start, end)
 
 	score, lali := obialign.FastLCSEGFScoreByte(
-		(*cseq)[start:end],
+		frg,
 		(*cpattern)[0:int(pattern.pointer.pointer.patlen)],
 		nerr, true, &buffer)
 
diff --git a/pkg/obiapat/pcr.go b/pkg/obiapat/pcr.go
index d9966e0..a99792c 100644
--- a/pkg/obiapat/pcr.go
+++ b/pkg/obiapat/pcr.go
@@ -255,8 +255,10 @@ func _Pcr(seq ApatSequence,
 								(opt.MinLength() == 0 || length >= opt.MinLength()) &&
 								(opt.MaxLength() == 0 || length <= opt.MaxLength()) {
 								amplicon, _ := sequence.Subsequence(fm[1], rm[0], opt.pointer.circular)
+								log.Debugf("seq length : %d capacity : %d",amplicon.Len(),cap(amplicon.Sequence()))
 								annot := amplicon.Annotations()
 								obiutils.MustFillMap(annot, sequence.Annotations())
+
 								annot["forward_primer"] = forward.String()
 
 								match, _ := sequence.Subsequence(fm[0], fm[1], opt.pointer.circular)
@@ -392,6 +394,7 @@ func _PCRSlice(sequences obiseq.BioSequenceSlice,
 			results = append(results, amplicons...)
 		}
 
+		log.Debugf("Number of sequences in the slice : %d",len(sequences))
 		for _, sequence := range sequences[1:] {
 			seq, _ = MakeApatSequence(sequence, options.Circular(), seq)
 			amplicons = _Pcr(seq, sequence, options)
@@ -400,7 +403,7 @@ func _PCRSlice(sequences obiseq.BioSequenceSlice,
 			}
 		}
 
-		// log.Println(AllocatedApaSequences())
+	    //log.Debugln(AllocatedApaSequences())
 
 		// seq.Free()
 	}
@@ -426,7 +429,9 @@ func PCRSliceWorker(options ...WithOption) obiseq.SeqSliceWorker {
 
 	opt := MakeOptions(options)
 	worker := func(sequences obiseq.BioSequenceSlice) obiseq.BioSequenceSlice {
-		return _PCRSlice(sequences, opt)
+		result :=  _PCRSlice(sequences, opt)
+		sequences.Recycle(true)
+		return result
 	}
 
 	return worker
diff --git a/pkg/obichunk/chunks.go b/pkg/obichunk/chunks.go
index f88e779..00e426b 100644
--- a/pkg/obichunk/chunks.go
+++ b/pkg/obichunk/chunks.go
@@ -46,7 +46,7 @@ func ISequenceChunk(iterator obiiter.IBioSequence,
 				for data.Next() {
 					b := data.Get()
 					*chunk = append(*chunk, b.Slice()...)
-					b.Recycle()
+					b.Recycle(false)
 				}
 
 				jobDone.Done()
diff --git a/pkg/obichunk/subchunks.go b/pkg/obichunk/subchunks.go
index 7250946..240d2f6 100644
--- a/pkg/obichunk/subchunks.go
+++ b/pkg/obichunk/subchunks.go
@@ -106,7 +106,7 @@ func ISequenceSubChunk(iterator obiiter.IBioSequence,
 					batch.Slice()[i] = nil
 				}
 
-				batch.Recycle()
+				batch.Recycle(false)
 
 				_By(func(p1, p2 *sSS) bool {
 					return p1.code < p2.code
diff --git a/pkg/obichunk/unique.go b/pkg/obichunk/unique.go
index aa3631b..0a81c86 100644
--- a/pkg/obichunk/unique.go
+++ b/pkg/obichunk/unique.go
@@ -97,8 +97,7 @@ func IUniqueSequence(iterator obiiter.IBioSequence,
 				// No more sub classification of sequence or only a single sequence
 				if opts.NoSingleton() && len(batch.Slice()) == 1 && batch.Slice()[0].Count() == 1 {
 					// We remove singleton from output
-					batch.Slice()[0].Recycle()
-					batch.Recycle()
+					batch.Recycle(true)
 				} else {
 					iUnique.Push(batch.Reorder(nextOrder()))
 				}
diff --git a/pkg/obiformats/fastseq_write_fasta.go b/pkg/obiformats/fastseq_write_fasta.go
index d9d1b88..20952a5 100644
--- a/pkg/obiformats/fastseq_write_fasta.go
+++ b/pkg/obiformats/fastseq_write_fasta.go
@@ -69,7 +69,7 @@ func WriteFasta(iterator obiiter.IBioSequence,
 	options ...WithOption) (obiiter.IBioSequence, error) {
 	opt := MakeOptions(options)
 
-	iterator = iterator.Rebatch(10000)
+	iterator = iterator.Rebatch(1000)
 	file, _ = obiutils.CompressStream(file, opt.CompressedFile(), opt.CloseFile())
 
 	newIter := obiiter.MakeIBioSequence()
diff --git a/pkg/obiformats/fastseq_write_fastq.go b/pkg/obiformats/fastseq_write_fastq.go
index eaf62ce..7825482 100644
--- a/pkg/obiformats/fastseq_write_fastq.go
+++ b/pkg/obiformats/fastseq_write_fastq.go
@@ -57,7 +57,7 @@ func WriteFastq(iterator obiiter.IBioSequence,
 	file io.WriteCloser,
 	options ...WithOption) (obiiter.IBioSequence, error) {
 
-	iterator = iterator.Rebatch(10000)
+	iterator = iterator.Rebatch(1000)
 
 	opt := MakeOptions(options)
 
diff --git a/pkg/obiformats/genbank_read.go b/pkg/obiformats/genbank_read.go
index 195c974..7bbb7cf 100644
--- a/pkg/obiformats/genbank_read.go
+++ b/pkg/obiformats/genbank_read.go
@@ -29,15 +29,16 @@ const (
 )
 
 func _ParseGenbankFile(source string,
-	input <-chan _FileChunk, out obiiter.IBioSequence) {
+	input <-chan _FileChunk, out obiiter.IBioSequence,
+	chunck_order func() int) {
 
 	state := inHeader
 
 	for chunks := range input {
-		log.Debugln("Chunk size", (chunks.raw.(*bytes.Buffer)).Len())
+		// log.Debugln("Chunk size", (chunks.raw.(*bytes.Buffer)).Len())
 		scanner := bufio.NewScanner(chunks.raw)
-		order := chunks.order
 		sequences := make(obiseq.BioSequenceSlice, 0, 100)
+		sumlength:=0
 		id := ""
 		scientificName := ""
 		defBytes := new(bytes.Buffer)
@@ -67,7 +68,7 @@ func _ParseGenbankFile(source string,
 			case strings.HasPrefix(line, "ORIGIN"):
 				state = inSequence
 			case line == "//":
-				log.Debugln("Total lines := ", nl)
+				// log.Debugln("Total lines := ", nl)
 				sequence := obiseq.NewBioSequence(id,
 					seqBytes.Bytes(),
 					defBytes.String())
@@ -80,10 +81,17 @@ func _ParseGenbankFile(source string,
 				annot["scientific_name"] = scientificName
 				annot["taxid"] = taxid
 				// log.Println(FormatFasta(sequence, FormatFastSeqJsonHeader))
-				log.Debugf("Read sequences %s: %dbp (%d)", sequence.Id(),
-					sequence.Len(), seqBytes.Len())
+				// log.Debugf("Read sequences %s: %dbp (%d)", sequence.Id(),
+				//	sequence.Len(), seqBytes.Len())
 
 				sequences = append(sequences, sequence)
+				sumlength+=sequence.Len()
+
+				if len(sequences) == 100 || sumlength > 1e7 {
+					out.Push(obiiter.MakeBioSequenceBatch(chunck_order(), sequences))
+					sequences = make(obiseq.BioSequenceSlice, 0, 100)
+					sumlength = 0
+				}
 				defBytes = new(bytes.Buffer)
 				featBytes = new(bytes.Buffer)
 				seqBytes = new(bytes.Buffer)
@@ -111,8 +119,10 @@ func _ParseGenbankFile(source string,
 			}
 
 		}
-		out.Push(obiiter.MakeBioSequenceBatch(order, sequences))
-	}
+		if len(sequences) > 0 {
+			out.Push(obiiter.MakeBioSequenceBatch(chunck_order(), sequences))
+		}
+}
 
 	out.Done()
 
@@ -125,6 +135,7 @@ func ReadGenbank(reader io.Reader, options ...WithOption) obiiter.IBioSequence {
 	newIter := obiiter.MakeIBioSequence()
 
 	nworkers := opt.ParallelWorkers()
+	chunck_order := obiutils.AtomicCounter()
 	newIter.Add(nworkers)
 
 	go func() {
@@ -133,7 +144,7 @@ func ReadGenbank(reader io.Reader, options ...WithOption) obiiter.IBioSequence {
 
 	// for j := 0; j < opt.ParallelWorkers(); j++ {
 	for j := 0; j < nworkers; j++ {
-		go _ParseGenbankFile(opt.Source(),entry_channel, newIter)
+		go _ParseGenbankFile(opt.Source(), entry_channel, newIter,chunck_order)
 	}
 
 	go _ReadFlatFileChunk(reader, entry_channel)
@@ -152,7 +163,6 @@ func ReadGenbankFromFile(filename string, options ...WithOption) (obiiter.IBioSe
 
 	options = append(options, OptionsSource(obiutils.RemoveAllExt((path.Base(filename)))))
 
-
 	reader, err = os.Open(filename)
 	if err != nil {
 		log.Printf("open file error: %+v", err)
diff --git a/pkg/obiiter/batch.go b/pkg/obiiter/batch.go
index 47b7b82..bf7ac2f 100644
--- a/pkg/obiiter/batch.go
+++ b/pkg/obiiter/batch.go
@@ -47,7 +47,7 @@ func (batch BioSequenceBatch) IsNil() bool {
 	return batch.slice == nil
 }
 
-func (batch BioSequenceBatch) Recycle() {
-	batch.slice.Recycle()
+func (batch BioSequenceBatch) Recycle(including_seq bool) {
+	batch.slice.Recycle(including_seq)
 	batch.slice = nil
 }
diff --git a/pkg/obiiter/batchiterator.go b/pkg/obiiter/batchiterator.go
index 6e86d82..927f46c 100644
--- a/pkg/obiiter/batchiterator.go
+++ b/pkg/obiiter/batchiterator.go
@@ -435,7 +435,7 @@ func (iterator IBioSequence) Rebatch(size int) IBioSequence {
 					buffer = obiseq.MakeBioSequenceSlice()
 				}
 			}
-			seqs.Recycle()
+			seqs.Recycle(false)
 		}
 
 		if len(buffer) > 0 {
@@ -461,11 +461,8 @@ func (iterator IBioSequence) Recycle() {
 		// iterator.Get()
 		batch := iterator.Get()
 		log.Debugln("Recycling batch #", batch.Order())
-		for _, seq := range batch.Slice() {
-			seq.Recycle()
-			recycled++
-		}
-		batch.Recycle()
+		recycled+=batch.Len()
+		batch.Recycle(true)
 	}
 	log.Debugf("End of the recycling of %d Bioseq objects", recycled)
 }
@@ -473,7 +470,7 @@ func (iterator IBioSequence) Recycle() {
 func (iterator IBioSequence) Consume() {
 	for iterator.Next() {
 		batch := iterator.Get()
-		batch.Recycle()
+		batch.Recycle(false)
 	}
 }
 
@@ -490,12 +487,8 @@ func (iterator IBioSequence) Count(recycle bool) (int, int, int) {
 			variants++
 			reads += seq.Count()
 			nucleotides += seq.Len()
-
-			if recycle {
-				seq.Recycle()
-			}
 		}
-		batch.Recycle()
+		batch.Recycle(recycle)
 	}
 	log.Debugf("End of the counting of %d Bioseq objects", variants)
 	return variants, reads, nucleotides
@@ -547,7 +540,7 @@ func (iterator IBioSequence) DivideOn(predicate obiseq.SequencePredicate,
 					falseSlice = obiseq.MakeBioSequenceSlice()
 				}
 			}
-			seqs.Recycle()
+			seqs.Recycle(false)
 		}
 
 		if len(trueSlice) > 0 {
@@ -688,7 +681,7 @@ func (iterator IBioSequence) Load() obiseq.BioSequenceSlice {
 		b := iterator.Get()
 		log.Debugf("append %d sequences",b.Len())
 		chunck = append(chunck, b.Slice()...)
-		b.Recycle()
+		b.Recycle(false)
 	}
 
 	return chunck
diff --git a/pkg/obiiter/distribute.go b/pkg/obiiter/distribute.go
index 45e755a..bba3f79 100644
--- a/pkg/obiiter/distribute.go
+++ b/pkg/obiiter/distribute.go
@@ -92,7 +92,7 @@ func (iterator IBioSequence) Distribute(class *obiseq.BioSequenceClassifier, siz
 					slices[key] = &s
 				}
 			}
-			seqs.Recycle()
+			seqs.Recycle(false)
 		}
 
 		for key, slice := range slices {
diff --git a/pkg/obiiter/workers.go b/pkg/obiiter/workers.go
index 8003851..b7adc6e 100644
--- a/pkg/obiiter/workers.go
+++ b/pkg/obiiter/workers.go
@@ -119,7 +119,7 @@ func (iterator IBioSequence) MakeISliceWorker(worker obiseq.SeqSliceWorker, size
 		for iterator.Next() {
 			batch := iterator.Get()
 			batch.slice = worker(batch.slice)
-			newIter.pointer.channel <- batch
+			newIter.Push(batch)
 		}
 		newIter.Done()
 	}
diff --git a/pkg/obiseq/biosequence.go b/pkg/obiseq/biosequence.go
index e38b685..76d0e9d 100644
--- a/pkg/obiseq/biosequence.go
+++ b/pkg/obiseq/biosequence.go
@@ -61,15 +61,20 @@ type BioSequence struct {
 }
 
 // MakeEmptyBioSequence() creates a new BioSequence object with no data
-func MakeEmptyBioSequence() BioSequence {
+func MakeEmptyBioSequence(preallocate int) BioSequence {
 	atomic.AddInt32(&_NewSeq, 1)
 	atomic.AddInt32(&_InMemSeq, 1)
 
+	seq := []byte(nil)
+	if preallocate > 0 {
+		seq = GetSlice(preallocate)
+	}
+
 	return BioSequence{
 		id:          "",
 		definition:  "",
 		source:      "",
-		sequence:    nil,
+		sequence:    seq,
 		qualities:   nil,
 		feature:     nil,
 		paired:      nil,
@@ -78,8 +83,8 @@ func MakeEmptyBioSequence() BioSequence {
 }
 
 // `NewEmptyBioSequence()` returns a pointer to a new empty BioSequence
-func NewEmptyBioSequence() *BioSequence {
-	s := MakeEmptyBioSequence()
+func NewEmptyBioSequence(preallocate int) *BioSequence {
+	s := MakeEmptyBioSequence(preallocate)
 	return &s
 }
 
@@ -87,7 +92,7 @@ func NewEmptyBioSequence() *BioSequence {
 func MakeBioSequence(id string,
 	sequence []byte,
 	definition string) BioSequence {
-	bs := MakeEmptyBioSequence()
+	bs := MakeEmptyBioSequence(0)
 	bs.SetId(id)
 	bs.SetSequence(sequence)
 	bs.SetDefinition(definition)
@@ -127,7 +132,7 @@ func (sequence *BioSequence) Recycle() {
 
 // Copying the BioSequence.
 func (s *BioSequence) Copy() *BioSequence {
-	newSeq := MakeEmptyBioSequence()
+	newSeq := MakeEmptyBioSequence(0)
 
 	newSeq.id = s.id
 	newSeq.definition = s.definition
diff --git a/pkg/obiseq/biosequenceslice.go b/pkg/obiseq/biosequenceslice.go
index 46d2380..3337512 100644
--- a/pkg/obiseq/biosequenceslice.go
+++ b/pkg/obiseq/biosequenceslice.go
@@ -34,14 +34,22 @@ func MakeBioSequenceSlice(size ...int) BioSequenceSlice {
 	return *NewBioSequenceSlice(size...)
 }
 
-func (s *BioSequenceSlice) Recycle() {
+func (s *BioSequenceSlice) Recycle(including_seq bool) {
 	if s == nil {
 		log.Panicln("Trying too recycle a nil pointer")
 	}
 
 	// Code added to potentially limit memory leaks
-	for i := range *s {
-		(*s)[i] = nil
+	if including_seq {
+		for i := range *s {
+			(*s)[i] .Recycle()
+			(*s)[i] = nil
+		}
+	
+	} else {
+		for i := range *s {
+			(*s)[i] = nil
+		}	
 	}
 
 	*s = (*s)[:0]
diff --git a/pkg/obiseq/merge.go b/pkg/obiseq/merge.go
index c84b232..ca1ea41 100644
--- a/pkg/obiseq/merge.go
+++ b/pkg/obiseq/merge.go
@@ -213,7 +213,7 @@ func (sequences BioSequenceSlice) Merge(na string, statsOn []string) *BioSequenc
 		}
 	}
 
-	sequences.Recycle()
+	sequences.Recycle(false)
 	return seq
 
 }
diff --git a/pkg/obiseq/pool.go b/pkg/obiseq/pool.go
index c03c6f7..08d2806 100644
--- a/pkg/obiseq/pool.go
+++ b/pkg/obiseq/pool.go
@@ -20,7 +20,9 @@ func RecycleSlice(s *[]byte) {
 		if cap(*s) == 0 {
 			log.Panicln("trying to store a NIL slice in the pool", s == nil, *s == nil, cap(*s))
 		}
-		_BioSequenceByteSlicePool.Put(s)
+		if cap(*s) <= 1024 {
+			_BioSequenceByteSlicePool.Put(s)
+		}
 	}
 }
 
@@ -28,7 +30,10 @@ func RecycleSlice(s *[]byte) {
 //
 // the slice can be prefilled with the provided values
 func GetSlice(capacity int) []byte {
-	p := _BioSequenceByteSlicePool.Get().(*[]byte)
+	p := (*[]byte)(nil)
+	if capacity <= 1024 {
+		p = _BioSequenceByteSlicePool.Get().(*[]byte)
+	}
 
 	if p == nil || *p == nil || cap(*p) < capacity {
 		s := make([]byte, 0, capacity)
diff --git a/pkg/obiseq/subseq.go b/pkg/obiseq/subseq.go
index 6cc5778..0e49da3 100644
--- a/pkg/obiseq/subseq.go
+++ b/pkg/obiseq/subseq.go
@@ -8,7 +8,6 @@ import (
 // Returns a sub sequence start from position 'from' included,
 // to position 'to' excluded. Coordinates start at position 0.
 func (sequence *BioSequence) Subsequence(from, to int, circular bool) (*BioSequence, error) {
-
 	if from >= to && !circular {
 		return nil, errors.New("from greater than to")
 	}
@@ -24,10 +23,11 @@ func (sequence *BioSequence) Subsequence(from, to int, circular bool) (*BioSeque
 	var newSeq *BioSequence
 
 	if from < to {
-		newSeq = NewEmptyBioSequence()
-		newSeq.Write(sequence.Sequence()[from:to])
+		newSeq = NewEmptyBioSequence(0)
+		newSeq.sequence = CopySlice(sequence.Sequence()[from:to])
 
 		if sequence.HasQualities() {
+			newSeq.qualities = CopySlice(sequence.Qualities()[from:to])
 			newSeq.WriteQualities(sequence.Qualities()[from:to])
 		}