In 2012, JBEI researchers, including Blake Simmons, a co-author on this new study, had discovered a suite
of saccharification enzymes that were tolerant to ionic liquids.
The pre-treatments make the complex carbohydrates more accessible to enzymes that convert them to glucose, in a process
called saccharification.
They varied the temperature and duration of steam explosion and then used a variety of physical and biochemical techniques to characterise what effects varying the pre-treatments had on the different types of sugars before and
after saccharification.
We then identified GH1 enzymes active at 70 °C and 20 % (v / v)[C2C1Im][OAc] over the course of a 24 -
h saccharification reaction.
In this method, pretreatment of corn fiber in a dilute acid solution at moderate temperature is followed by
enzymatic saccharification of cellulose, yielding up to 100 % of the sugar content of the hemicellulose without generating fermentation inhibitors.
Technological challenges remain, such as the need for more efficient enzymes
for saccharification, new microbes that can ferment multiple sugars, better integration of process steps, and improved methods for recovery of dilute ethanol.
Enzymes are then added to release the sugars from that gooey mixture of cellulose and hemicellulose, a step
called saccharification.
In a further study funded by the BBSRC / EPSRC Integrated Biorefining Research and Technology Club, the scientists discovered the key factors that determine the efficiency
of saccharification.
It combines novel processing of raw materials,
saccharification (conversion of biomass to intermediate cellulosic sugars), and fermentation to produce cellulosic ethanol.
With this strategy,
saccharification and fermentation are combined in a single process.