Process for producing cellulolytic enzymes
First Claim
1. A process for aerobic production of cellulase by cultivation of a Trichoderma reesei strain in a fermentation zone containing a nutrient medium, said process comprising feeding said fermentation zone with soluble sugar and being characterized by:
- (a) a first step of subjecting to aerobic fermentation conditions a culture medium comprising a Trichoderma reesei strain, an inorganic salt and an initial carbon substrate containing at least one cellulose containing material and at least one soluble sugar, the amount by weight of said cellulose and said soluble sugar, in proportion to the culture medium, being each 0.01-2%, the first step being continued without further soluble sugar addition for a sufficient time to consume at least 10% of the sugar and to obtain a sugar concentration in the medium lower than 0.3% by weight, and(b) a second step of continuing the aerobic fermentation by adding soluble sugar continuously so as to introduce a sugar amount totalling at least 3% by weight of the culture medium while maintaining the sugar concentration in said culture medium at a value lower than 0.3% by weight.
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Abstract
This invention concerns a process of producing cellulolytic enzymes by fermentation with the Trichoderma reesei fungus.
This process includes two steps:
(a) a first step of subjecting to aerobian fermentation a culture medium comprising a strain of Trichoderma reesei, nutrition compounds and a small quantity of cellulose and sugar,
(b) a second step of contining the aerobian fermentation by adding soluble sugar at a speed such that the sugar concentration in the fermentation zone remains under 0.3% by weight.
The cellulolytic enzymes obtained are used in the enzymatic hydrolysis of a lignocellulosic biomass.
28 Citations
10 Claims
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1. A process for aerobic production of cellulase by cultivation of a Trichoderma reesei strain in a fermentation zone containing a nutrient medium, said process comprising feeding said fermentation zone with soluble sugar and being characterized by:
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(a) a first step of subjecting to aerobic fermentation conditions a culture medium comprising a Trichoderma reesei strain, an inorganic salt and an initial carbon substrate containing at least one cellulose containing material and at least one soluble sugar, the amount by weight of said cellulose and said soluble sugar, in proportion to the culture medium, being each 0.01-2%, the first step being continued without further soluble sugar addition for a sufficient time to consume at least 10% of the sugar and to obtain a sugar concentration in the medium lower than 0.3% by weight, and (b) a second step of continuing the aerobic fermentation by adding soluble sugar continuously so as to introduce a sugar amount totalling at least 3% by weight of the culture medium while maintaining the sugar concentration in said culture medium at a value lower than 0.3% by weight. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification