Gram-positive bacteria of the species Lactococcus lactis or Streptococcus thermophilus having a very low surface proteolysis, processes for obtaining them and uses thereof

A gram-positive bacterium of the species Streptococcus thermophilus or Lactococcus lactis, wherein the gram-positive bacterium has been modified to decrease or abolish expression or activity of a surface protease by mutagenesis and to have increased production of a heterologous protein of interest as compared to an otherwise identical gram-positive bacterium that has not been modified to decrease or abolish expression or activity of the surface protease,

• wherein the surface protease comprises an amino acid sequence having at least 80% sequence identity with the sequence of SEQ ID NO:
• 1, and
• wherein SEQ ID NO:
• 1 is defined as follows:
• I-A-G-T-G-T-I-E-X1-D-G-X2-X3-G-X4-I-G-G-X5-X6-X7-K
• wherein
• X1 is histidine (H) or lysine (K);
• X2 is serine(S), alanine (A) or threonine (T);
• X3 is isoleucine (I), leucine (L) or valine (V);
• X4 is aspartic acid (D) or glutamine (Q);
• X5 is alanine (A) or valine (V);
• X6 is aspartic acid (D) or tyrosine (Y);
• and
• X7 is lysine (K) or leucine (L).