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Marek et al. ID #29
2008 International Conference on Flax and Other Bast Plants (ISBN #978-0-9809664-0-4) 159
Enzymatic Bioprocessing – New Tool of Extensive Natural Fibre Source
Utilization
ID number: 29
Marek Jan
1
, Antonov Viktor
1
, Bjelkova Marie
2
, Smirous Prokop
2
, Fischer Holger
3
,
Janosik Stefan
4
1
INOTEX, spol. s r.o., Stefanikova 1208, Dvur Kralove n.L., 544 01, Czech Republic
2
AGRITEC., Research, Breeding and Services Ltd., Zemedelska 16, 787 01 Sumperk, Czech
Republic
3
FIBRE, Faserinstitut Bremen e.V., Am Biologischen Garten 2, 283 59 Bremen,Germany
4
RIETER CZ, Nadrazni 696, 564 23 Zamberk, Czech Republic
marek@inotex.cz
Acknowledgement: This research was financially supported by Ministry of Agriculture CR
(grants No. QF 3068)
Abstract
New enzymes are going to have great potential in bast fibre processing and modification for different end
uses. There are several new technologies using enzymes able to modify fiber parametres, achieve desired
properties, improve processing results and ecology in the area of bast fibre processing and fabric
finishing. Enzymatic retting of flax, enzymatic cottonization of bast fibre, enzymatic hemp separation,
enzymatic processing of flax rovings before wet spinning etc. create a group of new technologies
supported by effective mechanical treatments
. A complex solution of relations between agrar and
processing sphere and the utilization of new technologies of biochemical and mechanical
processing enable the creation of suitable conditions to utilize traditional and perspective
renewable fibre sources and to open them to ways to new qualities and to other industrial areas
of use.
INTRODUCTION
Flax and hemp are low input crops that can be widely cultivated. Over decades many optimised
cultivars have been introduced, intensified agrotechnical procedures followed by carefully
tailored harvest methods and devices have been verified in the practice. Processes of fibre
extraction from the bast plant stems initiated by natural microbiological and biochemical
procedures, supported by specific climate conditions of typical planting regions fulfilled the
anticipated role.
However, increasing demand for quality and reproducibility of fibre processing and end-use
parameters gradually highlighted the imperfection caused by seasonal differences of weather
conditions during the crucial period of field dew retting.
The decisive influence of weather as well as more and more visible changes of climate led to the
reasonable problems within the whole cultivation and processing spheres.
Marek et al. ID #29
2008 International Conference on Flax and Other Bast Plants (ISBN #978-0-9809664-0-4) 160
On the other hand flax and hemp as well as all emerging technical plant sources of fibre become
more and more attractive as new, renewable biomaterials for technical use radically changing the
dominant role of crude oil based synthetic fibres, heavier glass fibres and cotton which are
typically heavy on water and dependent on a specific area of cultivation only.
All these facts underline the need to find a simple, guaranteed process to cut the influence of
climate and to bring about the possibility of a complex, waste-less utilization of cultivated crops.
Biotechnology – more specifically, selective enzymatic processes seems to be a clear answer.
The new strategy of “bio-retting” cuts the dependence on weather and climate, speeds the
process of fibre extraction and helps to get better elementarisation and fineness. The selectivity
of enzymatic processing enables us to think about new materials (bioresins, lignin, glue
components, extracts of bast plant biomass - essential oils, antioxidants etc.) which will multiply
the overall effective future of such renewable materials. Their full biodegradability increases
their value.
The possibility to govern bio-retting more intensively by use of specially tailored enzymatic
auxiliary agents, allows for the current separate cultivation systems of flax for fibre extraction
and linseed flax crops to be combined. This could be one of next reasonable improvements in
flax effectiveness and environmental advantageous processes.
Enzymes – new chance for reproducibility and effectiveness
Enzymes are natural biocatalysts that have great potential in catalysis of chemical compounds
decomposition and synthesis [3, 4]. Enzymes tested and used in different areas of the textile
industry bring many advantages and allow achievement of still unattainable results. This could
be a chance for cultivation and processing of bast fibre too. In fact conventional bast fibre
processing technology in Central Europe is dew-retting as a first fibre releasing operation as
compared to the water retting widely used 50 years ago and still allowed in China. All work
during this retting period is done by different enzymes coming from natural microorganisms
acting on the plant surface. Nevertheless dew-retting is negatively influenced by seasonal
variation of weather. The important part of under- and over- retted fibres is an undesirable
consequence.
A typical feature of enzymes is their selectivity. Enzyme biocatalysis works by low
concentration and is characterised by mild conditions of process (temperature, pH, humidity).
Enzymatic catalysis selectively focuses on the specific substrate composition. It eliminates the
risk of treated substrate damage opening the door for tailored specific technological effects and
process unification. Contrary to conventional chemistry less energy, water and chemicals is
needed. This places enzymatic procedures into the cleaner production tools [5]. The risk of
enzyme inactivation, caused by irreversible protein denaturation and the shift of the active centre
as the heart of “lock and key” principle of their work, must be avoided. The possibility of mutual
combination of enzymes with different substrate specific action broadens the area of use.
These advantages have initiated also the recent development of tailor made enzymatic mixtures
for bast fibre processing. During the dew-retting process enzymes must be able to attack the
natural components of technical (bast) plant stalk – such as pectin and lignin to support
extraction of fibres from the stalk building bundles. The main enzymes acting in retting process
are pectinases, xylanases and cellulases.
Marek et al. ID #29
2008 International Conference on Flax and Other Bast Plants (ISBN #978-0-9809664-0-4) 161
Enzymes can help in different stages of bast fibre processing like retting, cottonization,
improving pretreatment and others. They are able to prepare tailor-made materials for many
different applications, ring- and OE- spun yarns, automotive composites or building insulations
are among them.
The crucial moment for final fibre quality and yield is the retting stage [1, 2]. Basically there are
two alternate possibilities to apply enzymes to facilitate process of fibre separation, decortication
and cleaning: spraying of harvested stems on the field during the beginning of the dew-retting
process or as an additional wet processing step on decorticated bast fibre in the loose dyeing
device. Direct field spray application could be influenced by rapid change of weather (rain). The
longer the retting period on the field the higher the risk of material quality and / or yield losses.
Supported by specific conditions of treatment an additional wet processing step could be the
most effective alternative avoiding the nongovernable climate and weather conditions. In
comparison with the direct field application an additional drying step is needed. It is also
necessary to avoid risk of fibre agglomeration which could negatively influence the resulting
fibre quality (length, fineness).
Several specially tailored enzymatic auxiliary agents (Table I.) for bast fibre extraction and
elementarization improvement have been developed and tested in a specific model as well as in
bulk and field conditions.
TABLE I. Inotex enzymatic products for bast fibre extraction improvement
Name Substrate(s)
Texazym SC Pectin
Texazym BFE Pectin
Texazym DLG Hemicelluloses, cellulose
Texazym SCW Pectin, hemicelluloses
Texazym SER-3conc Pectin, hemicelluloses
Texazym SER-4conc Pectin, hemicelluloses, cellulose
Texazym SER-5conc Pectin, hemicelluloses, lipids
Texazym PF neu Saccharide glues
Texazym LOOK Polyphenols
Mechanical treatment (opening and cleaning)
Opening is the next processing step after field dew-retting (wet retting eventually). This process
helps to open the compact structure of the stalk by means of mechanical power. Separation of
wooden and fibrous parts of the plant is ensured. Extracted fibre cleanness depends on the
synergy of the preliminary (dew) retting and mechanical treatment intensity. Nevertheless this
step can reasonably influence the final quality of fibre, its yield and end-use properties.
Proportions between used and waste fibre source part – or high and low quality (short, dusty
fibres, shives) is affected in this stage.
Consequently this part of the INOTEX study has been focussed on the mechanical treatment step
and consequent link with the quality and yield of conventional and biobased (enzyme)
treatments. A very fruitful collaboration with RIETER CZ machinery development has been
started, resulting in the verified highly effective, simple and yield of quality fibre improving
Marek et al. ID #29
2008 International Conference on Flax and Other Bast Plants (ISBN #978-0-9809664-0-4) 162
machinery concept REA 120 (Fig. 1 and 2). In principle the smooth longitudinal mechanical
treatment (instead the usually used perpendicular – vertically oriented opening device action)
shows its positive influence on the percentual yield of fibre length, and minimised dusty and
poor quality part of treated raw material. Improved fibre fineness and better quality of
elementarisation process in the combination with tested enzymatic “bio-retting” procedures have
been clearly confirmed. The whole REA 120 machinery concept is spatially and energy effective
with acceptable level of acquisition costs. This part of study clearly confirmed the advantageous
multidisciplinary approach on the way to maximum effective, tailored bast fibre bioprocessing
system.
Fig. 1 and 2. REA 120 machinery concept for fibres opening and cleaning by Rieter CZ,
Zamberk
ENZYMATIC PROCESSING OF FLAX, HEMP AND LINSEED
The range of practical enzymatic treatment alternatives for processing of flax, hemp and linseed
stems and fibres have been studied.
Enzymatic enrichment of dew-retting process
Enzymatic enrichment of the dew-retting process by use of development range of INOTEX tailor
made enzymatic blends (Table I.) sprayed on the field before pull out or within first the 3 days of
dew-retting period.
Typical conditions:
Field area 0,50 ha, ie. approx. 2,5 tons of stems
Spray consumption 320 l/ha, enzymatic product dilution 1:20
Followed by common dew-retting, turbine scutching.
Best results used Texazym SER-3conc spray with a measured increase in long fibre yield (about
+ 43%).
Results of repeated seasonal trials confirmed the possibility of shortening retting time because all
enzymatically sprayed flax stem batches reached the scutching quality after 11-14 days of dew-
retting.
Marek et al. ID #29
2008 International Conference on Flax and Other Bast Plants (ISBN #978-0-9809664-0-4) 163
Repair of worse qualities of retted fibres
The tested product alternatives Texazym SCW, Texazym SER-3conc have been applied on the
worse retted qualities of flax fibre in the rutched stage of processing.
Weather – dependent conventional field dew-retting often results in significant material losses
(about 20%) due to the under retted or over retted fibre quality results.
The feasibility of quality improvement by use of an additional enzymatic retting step was
confirmed. Laboratory tests showed (Fig. 3) that specially tailored enzymatic blends applied
before hackling improves fineness, colour and cleanness of the fibres.
Fig. 3. Repair of worst quality dew-retted fibres with Texazym SCW
Material friendly cottonization of bast fibre
Due to the massive outflow of cotton spinning and textile processing to the low-wage countries
significant spare cotton spinning and wet processing capacities remain available for alternative
use. The high quality fashion niche products with high margin require the better, original
qualities of bast fibre and blended constructions, mostly with cotton. One of the possibilities is
the utilization of existing loose fibre dyeing devices for enzymatic cottonisation of bast – usually
flax fibres (Fig. 5). This process of tailored fibre length shortening opens the possibility for
spinning by use of OE or ring-spinning cotton industrial technology. Common techniques, using
strong mechanical processing in conventional systems (like Laroche, Trützchler, Temafa-Like
Line) (Fig. 6) to cut the material into staple lengths produces quite a high portion of very short
fibres and dust.
As an alternative, material friendly bast fibre cottonisation procedure, based on combination of
enzymatic pre-cottonisation followed by a gentle mechanical processing unit REA 120 (RIETER
CZ) has been approved. The enzymatic pre-cottonisation step based on the removal of gluey
layers of the bast fibre allows the following smooth mechanical treatment without cutting using
longitude processing on the REA 120 cleaning and opening device. Staple length is variable
from 30 to 120 mm. The effect of different commercial enzymes on hemp fibre fineness
Marek et al. ID #29
2008 International Conference on Flax and Other Bast Plants (ISBN #978-0-9809664-0-4) 164
improvement was tested in collaboration with Fiber Institute Bremen (Germany) (Fig. 4., Table
II.). INOTEX version Texazym BFE was the best one.
0
10
20
30
40
50
r
a
w fibr
e
s
so
d
a
t
re
a
te
d
Bio
p
rep
B
a
ylase
L
yv
e
l
in
Texazy
m
BFE
OFDA mean value in µm
Fig. 4. Effect of different commercial enzymes on the hemp fibre fineness improvement
Fig. 5. Device for wet processing of loose fibres (tows for example)
Table II. Effect of different commercial enzymes on the improvement of hemp fibre fineness
(fibre diameter) and tenacity
Sample type OFDA mean value in µm Tenacity in cN/tex
Raw fibres
43,4 ± 1,3 30,4 ±
1,3
Soda treated
29,7 ± 0,8 22,4 ±
0,8
Bioprep
26,4 ± 0,6 23,8 ±
0,6
Baylase
30,5 ± 0,7 23,8 ±
0,7
Lyvelin
27,6 ± 0,6 26,3 ±
0,6
Texazym BFE
22,8 ± 0,5 32,5 ±
0,5
Marek et al. ID #29
2008 International Conference on Flax and Other Bast Plants (ISBN #978-0-9809664-0-4) 165
Completed trials signalised, that a new material friendly cottonisation technology supported by
enzymatic pre-treatment opens the possibility of low-quality bast fibre utilization. The
combination of interfibre glue substances (pectin, lignin, hemicelluloses) enzymatic
decomposition and “fibre friendly” longitudinal (tangential) mechanical processing was used.
Resulting qualities of flax tow after conventional Laroche processing (Fig. 6) and combination of
enzyme (TEXAZYM BFE) with Laroche versus REA 120 mechanical processing clearly
signalised the real possibility of low quality raw material utilization (Table III.). Therefore
linseed flax quality was tested too and positive results have been achieved (Table IV.).
Fig. 6. Laroche cottonization line – in CEMOLEN Humpolec, CZ
TABLE III. Processing of flax scutching tow (low-quality) with Texazym BFE
TABLE IV. Processing of linseed (variety Amon) tow with Texazym BFE
Application of enzymes in order to utilize fibre from linseed straw
The above mentioned positive experience with the linseed flax treatment encouraged our next
trials. This could be an attractive chance for the multiplied utilization of linseed quality of
harvest.
Mechanical opening and cleaning Micronaire
Length
(mm)
Short fibres
(%)
LAROCHE 7,24 20,01 18,0
2x REA 120 8,34 22,48 8,6
Mechanical opening and cleaning Micronaire
Length
(mm)
Short fibres
(%)
Amon - LAROCHE 8,12 20,87 18,2
Amon - 2x REA 120 8,47 18,91 18,8
Amon - LAROCHE + REA 120 7,72 19,64 22,0
Marek et al. ID #29
2008 International Conference on Flax and Other Bast Plants (ISBN #978-0-9809664-0-4) 166
Several varieties of linseed were compared and more suitable linseed varieties for fibre
utilization were selected. Figure 7 shows that the variety Amon has the highest fibre yield per
hectare and therefore it was selected for further tests of enzymatic processing.
2,389
2,212 2,333
2,049
1,8
1,9
2
2,1
2,2
2,3
2,4
t.ha
-1
Amon Lola Flanders Biltstar
Fig. 7. Comparison of stem biomass yield of different linseed varieties
A specially developed enzymatic mixture Texazym SER-3conc was applied to linseed stems by
spraying the stems on the field after crop. Stems were then harvested after dew-retting and
processed in tow scutching line Charle and cleaned in REA 120 device in Rieter CZ, Zamberk.
TABLE V. Enzymatic processing of linseed stems, cultivar Amon
Table V. shows that parametres of enzymatically treated linseed fibre nearly meets the
requirements of industrial producers for natural fibres in building insulations.
Linen eco-yarns and pretreatment of flax roving
Recent development of enzymatic processes in the area of bast (and emerging natural technical
plant) fibre brings the opportunity that the complete environmentally friendly production scheme
based on enzymatic processing is only steps away. After the enzymatically boosted “bio-retting”
process described below, tailored fibre length cottonisation and low quality improvement,
enzymes also can be employed within the following steps of conventional textile production.
Instead of harsh chemicals (surfactants, alkali chlorite, hypochlorite based bleaching etc.), clean
production based on bio processing steps can overtake a significant part of the whole process.
This material is characterised by natural look, equalised colour of roving, minimum alkalinity of
treated fabric (whole rest alkalinity became one of critical Eco-tex 100 criteria) and waste water
(Table VI.) . “Bioscouring” as an environmentally friendly enzymatic step (Texazym SC)
selectively catalyses the decomposition of the fibre gluing substances (pectin). Loose wax
blocking water (and processing bath) absorptivity can be easily removed by lowered
Linseed stems
untreated
Linseed stems sprayed with
Texazym SER-3conc
Stem length (cm) 70,0
Stem technical length (cm) 50,1
Fibre yield after scutching (%) 35,6 37,3
Content of impurities (%) 19,1 16,2
Fibre yield after REA cleaning (%) 65,0 65,7
Content of impurities (%) 12,1 11,7
Marek et al. ID #29
2008 International Conference on Flax and Other Bast Plants (ISBN #978-0-9809664-0-4) 167
temperatures (50-60°C). Practical trials confirmed expected yarn parameters, enhanced level of
whiteness and possible shortening of processing time as a green light to increased utilization of
installed capacities. Additionally a new enzymatic agent Texazym PF has been launched to
significantly improve spinability and weaving properties of wet-spun linen yarns. Low dose 0,5 –
2 g/l of Texazym PF as the last step of bleaching of roving significantly reduced the risk of
lumps (called “flags”) during wet spinning. Improvement of weaving (lower breakage rate of
about 15% with corresponding loom capacity enhancement) was realised in large scale.
Bioscouring based on the enzymatic agent pectinase (pectate-lyase) is also a new, innovative,
cleaner, production process of linen fabric pretreatments.
TABLE VI. Improvement of whiteness after enzymatic „bio-retting“ for eco-yarn production –
comparison of Texazym SCW with other types of enzymes
CIELAB
Color
difference dE*
Hue dH* Lightness dL*
Chroma
dC*
Whiteness
(°Berger)
DP
DP
bleached
Original rove - 82,2 64,7 13,61 37,34 3188 2557
Texazym SCW 2,58 -0,01 -0,27 -2,56 49,11 3120 2138
Texazym DLG 1,70 -0,37 -0,34 -1,62 41,10 3111 2224
Inosample XN* 3,01 0,06 -1,64 -2,52 38,79 3137 2258
Inosample
VMG*
2,66 -0,48 -1,74 -1,96 40,41 3087 2280
Inosample BU* 3,19 -0,09 -2,05 -2,44 40,00 3043 2222
* Inosamples XN, VMG and BU are different types of hemicellulases in the stage of testing
Long term monitoring of the impact of enzymatic pretreatment on flax roving quality and
spinnability was carried out for production of middle-fine 78 Tex yarns (Table VII.). A
comparison among different enzymatically processed lots was done. Texazym DLG, which was
studied, proved to improve the roving spinnability significantly with a high reduction of lignin
content.
TABLE VII. Results of industrial trials with enzymatic treatment of flax rovings
Parametres 1 2 3 4
Lignin in roving % 3,54 3,68 3,30 3,77
Lignin after treatment % 0,26 0,11 0,14 0,46
Roving weight loss % 10,12 8,47 9,09 9,53
Whiteness (Taube) 22,00 26,11 23,88 22,59
Breakage in 100 hours 5,50 11,17 10,20 8,00
Yarn tensile strength N 17,66 15,25 15,35 14,68
Strength variation % 14,67 17,85 18,68 18,46
Technical bast fibre applications
Technical textiles and new materials based on fibrous substrates will overtake a more and more
significant role within the sustainable strategy of the textile sector. Natural renewable fibres
clearly signalise a major potential of use. Enzymes – are able to achieve the aim of better
resource reproducibility, enhancement of yield of exploitable crops which helps to establish long
Marek et al. ID #29
2008 International Conference on Flax and Other Bast Plants (ISBN #978-0-9809664-0-4) 168
term positions in volume consumption areas like automotive, building sector etc. New enzyme
based fibre surface modifications will play a significant role in the area of better compatibility
with the composite polymer matrix. Tailored fibre lengths and diameters maximize homogeneity
and solidity of composites. Fineness improvement (better elementarization supported by
enzymes) leads to reduction of water absorption capacity based on the reduction of microspaces
among fibres and reduction of the hemicellulose content which are mainly responsible for
undesirable absorptivity of natural fibre reinforced composites. Last – but not least, selective
enzymatic treatment focussed on fibre extraction should lead to the next step of technical plant
use – extraction of bio-resins and natural glue components. This will speed-up innovation
process leading towards fully biodegradable biocomposites.
RESULTS
INOTEX is a small innovation company specializing in wet processing of textiles (since 1949)
years ago emphasized industrial biotechnologies as one of the future challenging areas of textile
branch sustainability. Results of studies, growing experience based of numerous trials and recent
trends of in the global economy clearly affirm the correctness of this decision. Presented results
of part of the long term R&D program focused on the search for bio-based support of extended
use of natural renewable (bast) fibres explicitly demonstrated the fact, that there are real
possibilities of practical implementation. The range of newly tailored enzymatic auxiliary agents
has been successfully launched into different stages of flax and hemp processing. Starting by
boosted “bio-retting“ field spray applications through cottonisation as a special quality
production step and repair of the lower qualities of conventionally dew-retted fibre until the
improvement of “green-label“ ready attractive fashion textiles.
Under the influence of changing climate in traditional bast fibrous crop areas and because
accurately specified, reproducible parameters are becoming a more and more principal condition
of new technical reinforcement fibre use, positive results of tailor made bio-processing signalize
a good future.
A clear consolidated approach should be an effective way to guarantee the position of natural
bast and emerging technical plants on the market, to help improve the effectiveness of their
market chain for new mass technical uses in close cooperation with end-user industries, to avoid
failures in the building of new business opportunities and market for these renewable raw
materials.
Diversified possibilities to use all kinds of fibre qualities, supported by newly extracted products
from the plant biomass inclusive of knowledge of low quality on waste utilization will multiply
the whole, complementary effectiveness of production and minimise risk of farmers. The broad
variability of use will reduce todays non-acceptable pressure on the maximum price of limited
material alternatives (usually fibre or linseed oil only).
Let´s follow this trend to utilize new experiences – “learning by nature” by implementation of a
knowledge based bioeconomy. Renewable sources will surely play a continuously rising role in
the global economy.
Marek et al. ID #29
2008 International Conference on Flax and Other Bast Plants (ISBN #978-0-9809664-0-4) 169
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