Öl- und Gasforschung

Abstrakt

Optimization of bioethanol production from agro-biological resource at high temperature

Latifa Jamai

The cost of saccharine and starchy biomasses represents approximately
60% of the cost of producing first generation bioethanol.
Inputs, seeds, crop irrigation and crop transportation are
important energy factors to consider. In order to find alternative
substrates to costly and food competing biomasses, we explored
an agro-biological resource that is drought resistant and
tolerant to a wide range of soil and climatic conditions: Prickly
pear (Opuntia ficus-indica).
This work aims to optimize the production of first generation
bioethanol by Kluyveromyces marxianus YMEK23, a thermoresistant
yeast strain, from prickly pear juice; a substrate rich in
sugars (98g L-1). The use of a Box-Behnken experimental design
showed that the fermentation temperature and the medium
pH are the main parameters influencing ethanol production.
The impact of these factors was modeled in a second-degree
polynomial equation. The results showed that the maximum
amount of ethanol produced is 41 g L-1 obtained at 37°C and
at pH of 5. However, supplementing nitrogen has a limited
impact on ethanol production.
The kinetics of batch fermentation under optimum conditions,
showed a very active fermentation metabolism of K. marxianus
on this substrate, translated by an early and exponential production
of ethanol as well as a rapid consumption of sugars.
The maximum amount of ethanol (41 g L-1) was reached after
16 hours of fermentation only.