Oxidative cleavage and hydrolytic boosting of cellulose in soybean spent flakes by Trichoderma reesei Cel61A lytic polysaccharide monooxygenase

- T. reesei LPMO TrCel61A has oxidative activity on PASC and treated soy spent flake.
- TrCel61A has no activity on DP 5-6 cello-oligomers, galactan, and soy spent flake.
- TrCel61A shows C1 and C4 type oxidation with ESI-MS, MALDI-ToF, and HPAEC-PAD.
- Treatment with TrCel61A boosts endoglucanase hydrolytic depolymerization by 27%.

The auxiliary activity family 9 (AA9) copper-dependent lytic polysaccharide monooxygenase (LPMO) from Trichoderma reesei (EG4; TrCel61A) was investigated for its ability to oxidize the complex polysaccharides from soybean. The substrate specificity of the enzyme was assessed against a variety of substrates, including both soy spent flake, a by-product of the soy food industry, and soy spent flake pretreated with sodium hydroxide. Products from enzymatic treatments were analyzed using mass spectrometry and high performance anion exchange chromatography. We demonstrate that TrCel61A is capable of oxidizing cellulose from both pretreated soy spent flake and phosphoric acid swollen cellulose, oxidizing at both the C1 and C4 positions. In addition, we show that the oxidative activity of TrCel61A displays a synergistic effect capable of boosting endoglucanase activity, and thereby substrate depolymerization of soy cellulose, by 27%.