Bioethanol production by recycled Scheffersomyces stipitis in sequential batch fermentations with high cell density using xylose and glucose mixture

• Published in: Bioresource technology Vol. 219; pp. 319 - 329
• Main Authors: Santos, Samantha Christine, de Sousa, Amanda Silva, Dionísio, Suzane Rodrigues, Tramontina, Robson, Ruller, Roberto, Squina, Fabio Márcio, Vaz Rossell, Carlos Eduardo, da Costa, Aline Carvalho, Ienczak, Jaciane Lutz
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.11.2016
• Subjects: Acid treatment; Batch Cell Culture Techniques - methods; Biofuels; Biotechnology - methods; Cell Count; Ethanol - metabolism; Fermentation - physiology; Flocculation; Glucose - metabolism; Gradual temperature decrease; Propagation yeast biosystem; Saccharomyces cerevisiae - metabolism; Short-term adaptive action; Xylose - metabolism; Acid treatment; Propagation yeast biosystem; Short-term adaptive action; Gradual temperature decrease; Flocculation
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2016.07.102

•An innovative high cell density bioprocess for Scheffersomyces stipitis was developed.•Feasible cell reusability was possible at elevated flocculent biomass concentration.•Acid treatment was an effective and safe action for flocculation disruption.•The decrease in temperature was related to upper xylose consumption and EtOH productivity.•A short-term adaptation was achieved, reflected by increased aldo-keto reductase activity. Here, it is shown three-step investigative procedures aiming to improve pentose-rich fermentations performance, involving a simple system for elevated mass production by Scheffersomyces stipitis (I), cellular recycle batch fermentations (CRBFs) at high cell density using two temperature strategies (fixed at 30°C; decreasing from 30 to 26°C) (II), and a short-term adaptation action seeking to acclimatize the microorganism in xylose rich-media (III). Cellular propagation provided 0.52gdrycellweightgRS−1, resulting in an expressive value of 45.9gdrycellweightL−1. The yeast robustness in CRBF was proven by effective ethanol production, reaching high xylose consumption (81%) and EtOH productivity (1.53gL−1h−1). Regarding the short-term adaptation, S. stipitis strengthened its robustness, as shown by a 6-fold increase in xylose reductase (XR) activity. The short fermentation time (20h for each batch) and the fermentation kinetics for ethanol production from xylose are quite promising.