METHOD OF TREATING BACTERIAL CONTAMINATION IN A MICROALGAE CULTURE WITH PH SHOCK

摘要

Methods of treating contamination, particularly bacterial contamination, in an open culture of microalgae with organic carbon are described herein. The methods comprise reducing the pH of a culture for a period of time and then raising the pH of the culture, wherein the culture comprises the presence of a first acid and the culture is contacted with a second acid to reduce the culture pH from a first pH value to a second pH value. The culture is maintained at the second pH value for at least 5 minutes before the culture pH is raised from the second pH value by contact with a base.

主权项

1. A method of reducing bacterial contamination in a microalgae culture, comprising:
a. Preparing in an open culture in a first bioreactor a microalgae culture having or suspected of containing a contaminating population of bacteria, in the presence of a microalgal-growth sustaining amount of a first acid, wherein said first acid:
i. Is a carboxylic acid having a pKa in water of 0-12, and comprising one or more of acetic acid, pyruvic acid, propionic acid, palmitic acid, and malic acid, andii. Wherein said first acid is acetic acid, it provides said microalgae culture with a maintained amount of 7.5 g/L or less of the conjugate base of said first acid, thereby providing said microalgae culture with a first pH of 5.5-10.5; b. Removing a first fraction of said microalgae culture comprising a portion of said microalgae and said contaminating population of bacteria from said first bioreactor; c. Contacting said first fraction of said microalgae culture with a second acid having a pKa equal to or less than the pKa of said first acid, wherein a substantial portion of said second acid is made up of at least one acid other than said first acid, thereby reducing the pH of said first fraction of said microalgae culture to a second pH greater than 0; d. Maintaining said first fraction of said microalgae culture at said second pH value for a period of at least 5 minutes, thereby reducing said population of viable bacteria in said first fraction of said microalgae culture; e. Contacting said first fraction of said microalgae culture with a base, such that the pH of said first fraction of said microalgae culture is raised above the pKa value of said first acid, thereby providing said microalgae culture having a reduced bacterial contamination; and f. Returning said first fraction of said microalgae culture to said first bioreactor, wherein said first fraction of said microalgae culture is mixed with said microalgae culture in said first bioreactor.