EFFECTS of Coconut Shell Hydrolyzate Inhibitors
Green in Second Generation Ethanol Production By
saccharomyces Cerevisiae Genetically Modified
Name: MATHEUS SILVA LAGE
Publication date: 03/02/2020
Advisor:
Name |
Role |
|---|---|
| ALEXANDRE MARTINS COSTA SANTOS | Co-advisor * |
| PATRICIA MACHADO BUENO FERNANDES (M/D) | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| ALEXANDRE MARTINS COSTA SANTOS | Co advisor * |
| IARA REBOUÇAS PINHEIRO | Internal Examiner * |
| PATRICIA MACHADO BUENO FERNANDES (M/D) | Advisor * |
Summary: Ethanol production from lignocellulosic waste is one of the main renewable sources to supply
the growing energy demand and contribute to the production of conventional fuels. Green
coconut shell is a waste discarded by the ton, becoming an environmental problem. Therefore,
its use for the production of second generation ethanol is a sustainable solution for the industry.
To obtain ethanol, lignocellulosic biomass undergoes physical and chemical treatments to
make fermentable sugars available. However, sugars come with compounds that inhibit the
growth and fermentation of microorganisms, including the yeast Saccharomyces cerevisiae,
the main organism used in the industrial production of ethanol. Considering the impact that the
inhibitory compounds have on the second generation ethanol yield, the objective of the present
work was to evaluate the effects of the main inhibitors of the green coconut husk, individually
and in association, on the growth and fermentation by a genetically modified S. cerevisiae
strain. The test results showed that weak acids (acetic acid and formic acid) in synthetic
medium negatively affect the growth rate of the G2-104 strain, but do not harm ethanol titers
when evaluated under viable conditions for the development of the strain. The 4-
hydroxybenzoic acid is the main phenolic compound present in green coconut biomass and
did not have negative effects on growth and fermentation by the strain within the concentrations
evaluated. In addition, when added together with a high concentration of formic acid, the
performance of the strain improved when compared to the fermentative profile of yeast in the
presence of formic acid individually. In coconut hydrolysates, the strain obtained ethanol yields
close to the result obtained in synthetic medium, even with the addition of more inhibitory
compounds to the medium, demonstrating that the strain has tolerance and good performance
in this type of hydrolysate.
