Enzymatic hydrolysis of pelletized AFEX™-treated corn stover at high solid loadings

• Published in: Biotechnology and bioengineering Vol. 111; no. 2; pp. 264 - 271
• Main Authors: Bals, Bryan D., Gunawan, Christa, Moore, Janette, Teymouri, Farzaneh, Dale, Bruce E.
• Format: Journal Article
• Language: English
• Published: United States Blackwell Publishing Ltd 01.02.2014; Wiley Subscription Services, Inc
• Subjects: AFEX; Ammonia; Ammonia - metabolism; Biomass; Biotechnology; Biotechnology - methods; Cellulose - metabolism; Corn; densification; depot; Glucose - isolation & purification; Hydrolysis; liquefaction; pelletization; regional processing; Xylose - isolation & purification; Zea mays - drug effects; Zea mays - metabolism; liquefaction; pelletization; densification; depot; regional processing; AFEX
• ISSN: 0006-3592; 1097-0290
• DOI: 10.1002/bit.25022

ABSTRACT Ammonia fiber expansion (AFEX™) pretreatment can be performed at small depots, and the pretreated biomass can then be pelletized and shipped to a centralized refinery. To determine the feasibility of this approach, pelletized AFEX‐treated corn stover was hydrolyzed at high (18–36%) solid loadings. Water absorption and retention by the pellets was low compared to unpelletized stover, which allowed enzymatic hydrolysis slurries to remain well mixed without the need for fed‐batch addition. Glucose yields of 68% and xylose yields of 65% were obtained with 20 mg enzyme/g glucan and 18% solid loading after 72 h, compared to 61% and 59% for unpelletized corn stover. Pelletization also slightly increased the initial rate of hydrolysis compared to unpelletized biomass. The ease of mixing and high yields obtained suggests that pelletization after AFEX pretreatment could have additional advantages beyond improved logistical handling of biomass. Biotechnol. Bioeng. 2014;111: 264–271. © 2013 Wiley Periodicals, Inc. AFEX is a unique pretreatment in that it can be performed at small depots followed by pelletization and shipping to large biorefineries. The authors have demonstrated that these pellets are effectively saccharified at high solid loading despite a decrease in water retention. Due to the low water retention, mixing during high solid hydrolysis is greatly improved.