DEVELOPMENT AND VERIFICATION OF AN INNOVATIVE FULL LIFE SUSTAINABLE APPROACH TO THE VALORISATION OF MUNICIPAL SOLID WASTE INTO INDUSTRIAL

FEEDSTOCKS

www.waste2go.eu

Work Package 5: Process development for cellulose degradation

Malcolm Lock (CPI)Brussels14 - 15 September 2015

Introduction• WP5 Objectives

• Process challenges

• Developing mixing strategies: Biomixer MR2

• The Biomixer in action

• Solid-liquid separation technologies

• Downstream processing using the Hydropress

• Production of materials for WP6

• WP5 Conclusions

WP5 Objectives

• Utilizing waste feedstocks from WP2 – data for feedstock development

• Application of specific enzyme combinations from WP3

• Process optimization for mixing cellulosic feedstock with enzymes

• Solid-liquid DSP to provide feedstocks for WP6 process developments

Process challenges for WP5• Require 15 – 20% (dw/w) loadings for acceptable yields

• Dry weight

– Cellulosic wastes have a high water content

• Substrate composition

– Cellulose low percentage of total weight

– Cellulose content varies between waste streams and batches

– Inhibitory components (e.g. metals from inks)

– pH altering factors (CaCO3 as paper whitener)

• Accessibility of cellulose for degradation

– Proportion trapped as crystalline cellulose

– Pre treatment designed to increase accessibility

• Batched at start or batch fed process (building up to target dw after liquefaction)?

• Enzyme combination

• Even at 6% dry weight solids loadings cellulosic suspensions have a high viscosity

• Rusden impellors are not satisfactory for mixing dense / viscous materials

– Impellor shape does not aid mixing

– Compaction in column fermentor increases viscosity

• Alternative mixing strategies needed to be employed:

Ribbon blender (bread and cheese

manufacturing)

Rotary augar (waste processing)

Process challenges: Mixing

• Horizontal mixing more efficient

• ‘Lift and drop’ action maximises substrate coating with enzyme

• Thermal jacket to control reaction temperature, data logging for multiple probe options

• Consideration of loading and unloading operations

Stainless Steel Horizontal Drum Reactor/Mixer

T

PH Addition

Three-Blade-Mixing-Insert

Motor (variable speed control)

PH Indicator

Thermocouple and Trip

Lute to remove any gas build-up

Sample take-off

Heated Jacket

Viewing Port/Filling Hatch

Heated Jacket

A-Frame Support and

tilt mechanism

to aid emptying of

vessel

Control Box.Process Temperature

Measurement, Temperature Control &

Trip.PH Monitoring.

Motor RPM Control.Data Logging.

E-STOP BUTTON

Process Media Temperature

Thermocouple

T

Motor Support and Shaft Seal

Mixer Blade Shaft Bearing Support

One end of Vessel to have a sealed hinged door opening and viewing port to assess liquefaction

Tilt-Wheel/Pivot Point to allow 30 degrees tilt either side from horizontal

Blade/Mixer Insert to have minimal clearance to inside of Mixer side wall

Process challenges: Designing a mixing vessel

Biomixer MR2 Features – Mixing

• Replaceable tri bladed impellor

• Designed to “lift and drop” high viscosity materials, coating with enzyme solution

• Drilled holes create vortex mixing once liquefaction has occurred

Biomixer MR2 – Data logging

• Data collected through back plate mounted sensors: pH and temperature

• Data logged through Eurotherm Chessel

• Impellor driven by inline motor, 0.37kW, with 40:1 step down gearbox

• Water jacket provides reaction temperature (Hüber recirculating water bath)

Biomixer MR2 – Loading and unloading

• Top port modifiable (e.g. solids loading chute), currently acting as lute

• Rotation for ease filling and unloading

• 50L working volume just fills vessel to below half

• Sealed hatch to enable easy loading or unloading

Biomixer MR2 in action

A. Starting material B. 23 hours C. 30 hours D. 48 hours

E. 59 hours F. 95 hours G. 99 hours decanted material

• Biomixer run 8 (20th to 23rd March 2015),

• MaCel45a digest (11.75 g.kg (dw)-1 in terms of total protein)

• Acetic acid washed office white paper at 20.1% (w/v) dry weight

• 12.95 kg batched at start with 12.95 kg added after 4.5 h

Biomixer MR2 in action

• Run 9: After batch addition solids • 17.5 % dw/v loading• Balling and lift-drop action• Full slurry never formed

• Run 3: Early trial with commercial enzyme

• 24.7% dw/v loading• Rapid development of thick slurry

• Viscosity

• Particle size of solids

• Percentage solids content

• Throughput requirements

• Reaction of slurry to pressure

• Target dry weight of produced solids

Centrifuge Filter press Gaffe bag

X X X

Solid-liquid separation technologies

Downstream processing using the Hydropress

• Lancman VSPX-98

• 98L capacity: 40L minimum working

volume

• Scalable technology (beer production)

• Pressure range 0.1 – 2.9 bar

• Process time dependent dewatering

• Filter media available

• Polypropylene monofilament lining bag

(average 106 µm pore size)

Samples for fractionation trials• Direction from WP3: LPMO + MtCDH and MaCel45a yielded highest DP fragmentation

• Dry Mixed Recycling and White Paper as substrates

• Liquefaction observed in flask trials with both substrates and both LPMOs

• Enzymes loaded with 1:1:1 ratio based on volume (concentrations comparable)

• Batched at start with one solids addition after 24 h

• Recoveries restricted by retention of sticky solids on Biomixer frame and CO2 release

• Hydropress produced solids with low water content

Run # Enzymes used Run time Waste typePercentage

loading (dw)Solids weight

(kg)Liquid weight

(kg)[Glucose] (g/L)

[Lactic acid] (g/L)

Recovery (%)Post

hydropress dry weight %

4 LPMO 3328, MtCDH, MaCel45a

99h15 Dry Mix Recycling 16.8 15.751 22.468 0.00 5.55 89.17 44.5

5 LPMO 3328, MtCDH, MaCel45a

101h15White paper & Dry

Mix Recyc14.7 11.28 32.84 0.02 1.05 85.63 43.4

6 LPMO 2916, MtCDH, MaCel45a

98h40 Dry Mix Recycling 16.8 16.16 31.45 0.34 0.10 94.80 43.6

8 MaCel45a 97h10Acid washed white

paper20.1 11.56 15.87 0.12 0.04 91.77 41.9

9 LPMO 3328 & MtCDH 28h15Acid washed white

paper17.5 NR NR 0.11 0.05 NR NR

Samples for fractionation trials

• Run 5 logged data showing stable pH and temperature control, motor current draw and stable rotation of the impellor

Samples for fractionation trials

Run 5 soluble sugar release with LPMO 3328 Run 6 soluble sugar release with LPMO 2916

Assuming entire added mass is cellulosic:

• 10.3% conversion to soluble sugars

• 3.62% yield soluble sugars

Assuming entire added mass is cellulosic:

• 26.1% conversion to soluble sugars

• 5.72% yield soluble sugars

0 1 2 3 4

24

48

72

96

Product

Concentration (g/L)

Tim

e (H

ours

) Cellotetraose (g/L)

Cellotriose (g/L)

Cellobiose (g/L)

Lactic acid (g/L)

Glucose (g/L)

WP5 Conclusions• Demonstration of high dry weight cellulose slurry mixing by Biomixer MR2

• Sterility (no lactic acid production) can be maintained within Biomixer setup at elevated temp

• DSP technologies for solid-liquid separation investigated

• Hydropress sufficient for W2G separation requirements

• Adequate mixing enabled production of soluble polysaccharides

• Analytical capability at CPI cannot analyse insoluble polysaccharide breakdown

• Scale up of process optimization factors exceedingly challenging

• Range of soluble and insoluble polysaccharides from different enzyme digestions of varying

waste cellulose feedstocks provided to WP6