Production process and formulation of a single-cell protein by fermenting the yeast kluyveromyces marxianus

A process to obtain a single-cell protein using a strain of Kluyveromyces marxianus (KMPROTEO1), which has been deposited under the terms of the Budapest Treaty, with accession number CM-CNRG TB66, characterized in that it comprises the following steps:

• (i) Reactivating yeast strain KMPROTEO1 in a Petri dish using YPD agar for 48 hours at a temperature of between 35° C. and 38° C.;
• (ii) Inoculating from the Petri dish to 20 ml liquid medium using 4 tubes with 5 ml of medium in suspension with an optical density of 1.0, maintaining the inoculum between 35° C. and 38° C. for 4 to 8 hours;
• (iii) Transferring the culture from the preceding step to a flask with P50 medium comprising:
• P50 fermentation medium
• Dextrose
• 30
• g/L
• Ammonium sulfate
• 2
• g/L
• Magnesium sulfate
• 0.5
• g/L
• Monopotassium phosphate
• 1.5
• g/L
• Yeast extract
• 2.5
• g/L
• fermenting for 4 to 8 hours maintaining a temperature of 35° C. to 38° C. with stirring between 100 and 250 rpm, with a pH between 5 and 5.5 and an aeration level between 0.5 and 2 volumes of air/volume of medium per minute (vvm);
• (iv) Transferring the culture from the preceding step to a flask with P50 medium comprising:
• P50 fermentation medium
• Dextrose
• 30
• g/L
• Ammonium sulfate
• 2
• g/L
• Magnesium sulfate
• 0.5
• g/L
• Monopotassium phosphate
• 1.5
• g/L
• Yeast extract
• 2.5
• g/L
• fermenting for 4 to 8 hours maintaining a temperature of between 35° C. and 38° C. with stirring between 100 and 250 rpm with a pH between 5 and 5.5 and an aeration level between 0.5 and 2 vvm;
• (v) Transferring the culture from the preceding step to the seed reactor which contains the P50 medium comprising:
• P50 fermentation medium
• Dextrose
• 30
• g/L
• Ammonium sulfate
• 2
• g/L
• Magnesium sulfate
• 0.5
• g/L
• Monopotassium phosphate
• 1.5
• g/L
• Yeast extract
• 2.5
• g/L
• fermenting for 4 to 8 hours maintaining a temperature of 35° C. to 38° C. with stirring between 100 and 250 rpm with a pH between 5 and 5.5 and an aeration level between 0.5 and 2 vvm;
• (vi) Transferring the culture from the preceding step to the production reactor which contains the medium comprising:
• P50 fermentation medium
• Dextrose
• 30
• g/L
• Ammonium sulfate
• 2
• g/L
• Magnesium sulfate
• 0.5
• g/L
• Monopotassium phosphate
• 1.5
• g/L
• Yeast extract
• 2.5
• g/L
• fermenting for 12 to 23 hours maintaining a temperature of 35° C. to 38° C. with stirring between 100 and 250 rpm with a pH between 5 and 5.5 and an aeration level between 0.5 and 2 (vvm), maintaining the concentration of dextrose in the medium between 1 g/L and 2 g/L;
• (vii) Centrifuging the mixture at 6,000 rpm, separating the mixture into two phases, pumping the light phase to a tank and the heavy phase to a second tank;
• (viii) Re-suspending the heavy phase in the same amount of removed water, centrifuging again following the specifications of the preceding step, and performing this process twice;
• (ix) Re-suspending the heavy phase in the reaction tank and adjusting the percentage of solids to 10%;
• (x) Adding the enzyme cellulase in a proportion of between 0.1% and 0.2% of wet biomass, maintaining a temperature between 55° C. and 60° C. for no less than 6 hours and no more than 12 hours with stirring between 100 and 250 rpm, maintaining the pH between 5 and 5.5, where the pH is adjusted to 7 when this step is completed;
• (xi) Raising the temperature between 65° C. and 75° C. and maintaining it for 15 to 30 minutes;
• (xii) Evaporating the mixture until concentrating the solids within the operating range of between 20% and 30% of solids in the mixture;
• (xiii) Drying in a spray dryer at an inlet temperature between 185° C. and 195° C. and an outlet temperature between 70° C. and 80° C.;
• (xiv) Recovering the powder from the dryer and packaging it in food-grade bags.