AgsE-deficient strain

A method for the production of a compound of interest by microbial fermentation, wherein the compound of interest is selected from the group consisting of an enzyme and a metabolite, the method comprising:

• a. providing a mutant filamentous fungal host cell capable of expressing the compound of interest, wherein said mutant filamentous fungal host cell has been modified in its genome to result in a deficiency in the production of a polypeptide compared with a parent filamentous fungal host cell which has not been modified, and wherein both said mutant and said parent filamentous fungal host cell is measured under the same conditions, wherein the polypeptide is selected from the group consisting of:
• i. a polypeptide comprising the amino acid sequence of SEQ ID NO:
• 3 or a polypeptide at least 90% identical thereto and having an enzymatic activity of the amino acid sequence of SEQ ID NO:
• 3;
• ii. a mature polypeptide comprised in the amino acid sequence of SEQ ID NO:
• 3 or a polypeptide at least 90% identical thereto and having an enzymatic activity of the mature polypeptide comprised in the amino acid sequence of SEQ ID NO:
• 3;
• and
• iii. a polypeptide encoded by the polynucleotide sequence of SEQ ID NO:
• 1 or 2 or encoded by a polynucleotide at least 90% identical to SEQ ID NO:
• 1 or 2, wherein said polypeptide encoded by a polynucleotide at least 90% identical to SEQ ID NO:
• 1 or 2 has an enzymatic activity of the polypeptide encoded by the polynucleotide sequence of SEQ ID NO:
• 1 or 2;
• b. culturing said mutant filamentous fungal host cell under conditions conducive to the expression of the compound of interest, and
• c. optionally isolating the compound of interest from the culture medium;
• wherein, in the mutant filamentous fungal host cell, the modification in its genome is selected from:
• A) a full or partial deletion of SEQ ID NO:
• 1 or a polynucleotide at least 90% identical to SEQ ID NO:
• 1;
• B) a full or partial replacement of SEQ ID NO:
• 1 or a polynucleotide at least 90% identical to SEQ ID NO:
• 1 with a polynucleotide sequence which does not code for a polypeptide as defined in a) i. or a) ii. or with a polynucleotide sequence which codes for a partially or fully inactive form of a polypeptide as defined in a) i. or a) ii.;
• and
• C) a disruption of SEQ ID NO:
• 1 or a polynucleotide at least 90% identical to SEQ ID NO:
• 1 by the insertion of one or more nucleotides in the polynucleotide sequence and consequent partial or full inactivation of a polypeptide as defined in a) i. or a) ii;
• wherein the polypeptide according to i. to iii. has an enzymatic activity which is α-1,3-glucan synthase enzymatic activity;
• and
• wherein the mutant filamentous fungal host cell further comprises at least one polynucleotide coding for the compound of interest and/or at least one polynucleotide coding for a polypeptide involved in the production of the compound of interest.