Improved Cellulosic Ethanol Titres from Highly Lignified Cotton Trash Residues Using Various Batch and Fed-Batch Process Configurations

  • S. McIntosh
  • J. Palmer
  • M. Egbuta
  • L. Liu
  • Tony VancovEmail author


This study investigates a fed-batch simultaneous saccharification fermentation (F-SSF) process to increase ethanol titres from highly lignified (41.6 wt.%) cotton gin trash residue. The optimal initial solid loading, enzyme dose, feed quantities and intervals to maximize substrate feed and subsequent ethanol titres were examined. Under batch SSF conditions, initial extracted cotton gin trash (ECGT) solid loadings were maximised at 19.35 wt.% and attained an ethanol titre of 23.3 g/l with a corresponding yield of 53.7%. Operating under optimised F-SSF mode, fermentations were initiated with 16.13 wt% EGCT solids followed by fresh ECGT feeds of 16.13 wt% and 12.9 wt.% at 12-h intervals. Cellulase levels were maintained at 44 FPU/g glucan throughout the fermentations. The final ethanol titre of 41 .4 g/l with a corresponding conversion rate of 70.1% was achieved after 72 h. Comparable ethanol yields of 40 g/l with 67.8% conversion were realized with lower cellulase dosing (25 FPU g/glucan) but only after extending the fermentation by 24 h.


Cotton gin trash Fed-batch SSF High solid loading Saccharomyces cerevisiae strain Fali® 



Financial support was provided by Cotton Research Development Corporation (CRDC) for this work and NSW Department of Primary Industries (NSW DPI) and Southern Cross University (SCU).

Compliance with Ethical Standards

Conflict of Interest

The authors declare that they have no conflict of interest.

Supplementary material

12155_2019_10023_MOESM1_ESM.pdf (8 kb)
Figure S1 Correlation between final (96 h of hydrolysis) glucose concentration, glucan digestion and substrate load. (PDF 7 kb)
12155_2019_10023_MOESM2_ESM.pdf (8 kb)
Figure S2 Correlation between final (96 h SSF) ethanol titre, ethanol yield and substrate load. (PDF 8 kb)


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Copyright information

© Crown 2019

Authors and Affiliations

  1. 1.NSW Department of Primary IndustriesWollongbar Primary Industries InstituteWollongbarAustralia
  2. 2.Southern Cross Plant ScienceSouthern Cross UniversityLismoreAustralia

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