p Coumaric acid inhibits anaerobic digestion of lignocellulose, - PowerPoint PPT Presentation

p ‐ Coumaric acid inhibits anaerobic digestion of lignocellulose, laccase detoxifies Michel Schroyen, Stijn Van Hulle, Han Vervaeren & Katleen Raes

Overview (1) Lignocellulose Pretreatment Anaerobic Agricultural waste Thermal digestion Forestry residue Chemical Biological 2

Lignocellulose “ You can make anything out of lignin , except money .” 3

Lignin & BMP Substrate Lignin % BMP Ensilage 1 308 Corn Stover 4,5 231 Wheat Straw 6 226 330 Flax Straw 8,6 232 Hemp Straw 9,2 240 BMP after 30 days 280 Miscanthus 12 140 (Nl/kgVS) Willow 17 92 230 Schroyen et al. 2015 (Bioresource Technology) 180 130 80 0 5 10 15 20 4 Lignin (g/100g)

Lignin Degradation Lignocellulose Pretreatment = Lignin degradation 5

TPC & BMP 30 25 Hydrolysis rate (Nl/kgVS/d) 20 15 10 5 0 0 50 100 150 200 250 300 Phenolic compounds (mg/l) 6

Overview (2) Lignocellulose Pretreatment Anaerobic Agricultural waste Thermal digestion Forestry residue Chemical Inhibitors Phenolic compounds 7

Experimental Setup (1) S Miscanthus / Hemp straw p ‐ Coumaric acid PC 0 – 2000 mg/l AD BMP – determination 8

Inhibition anaerobic digestion S PC AD Miscanthus Hemp straw • The hydrolysis rate during anaerobic digestion of miscanthus is reduced by p ‐ coumaric acid 9

Experimental Setup (2) S Miscanthus / Hemp straw p ‐ Coumaric acid PC 0 – 500 mg/l Laccase / Versatile E peroxidase 10

Detoxifying effect of enzymes S PC Laccase Versatile Peroxidase E • Laccase diminishes the concentration of p ‐ coumaric acid 11

Impact on the enzymes S PC Uninhibited Versatile E activity Laccase peroxidase 120 Relative enzyme activity 100 80 60 40 20 0 ‐ 20 • 500 mg/l inhibits versatile peroxidase completely 12

Overview (3) Pretreatment Lignocellulose Anaerobic Thermal Agricultural waste digestion Chemical Forestry residue Detoxification Laccase 13

Experimental Setup (3) S Miscanthus / Hemp straw p ‐ Coumaric acid PC 0 – 2000 mg/l E BMP ‐ determination AD 14

Connecting the dots S PC E AD • A laccase detoxifying step has a positive effect on hydrolysis as well as on total biogas production 15

Conclusion • Lignin has a negative impact on BMP • Increase of phenolic compounds inhibits anaerobic digestion of miscanthus • Versatile peroxidase is inhibited • Laccase detoxifies and can be used as an extra step in the production process 16

Thank you! Contact details: michel.schroyen@ugent.be