Effect of nitrogen-mediated changes in alkalinity on pH control and CO/sub 2/ supply in intensive microalgal cultures

Journal Article · Mon Mar 01 04:00:00 EST 1982 · Biotechnol. Bioeng. Symp.; (United States)

DOI:https://doi.org/10.1002/bit.260240308· OSTI ID:5298304

Goldman, J C; Dennett, M R; Riley, C B

The freshwater alga Scenedesmus obliquus was grown in continuous culture at a fixed dilution rate of 0.5/day, but at varying pH in the range 4.17-10.67. The pH was regulated in the range 4.17-7.67 by continuously bubbling 1% CO/sub 2/-enriched air into the cultures and by varying the source of nitrogen (NO/sup -//sub 3/, NH/sup +//sub 4/, or urea) in the growth medium, which, in turn, led to changes in culture alkalinity. Culture alkalinity and P/sub CO/sub 2// were the sole determinants of pH. A pH-stat system, together with NO/sub 3/ in the medium, was used to regulate the pH in the range 7.92-10.67. Maximum productivity, which occurred at pH 6.6, was dependent on N source only to the extent that culture alkalinity was a function of nitrogen uptake. The results demonstrate that the source of N because it leads to destruction of culture alkalinity and concomitant growth-inhibiting reductions in pH, whereas NO/sup -//sub 3/ has an opposite effect, although pH is not so severely affected in this case. Urea is, by far, the most suitable N source for maximizing algal yield when it is supplied in combination with the proper amounts of HCO/sub 3/ alkalinity in the growth medium and percent CO/sub 2/ in the bubbled gas that will lead to an equilibrium pH near the optimum pH.

• Research Organization: Woods Hole Oceanographic Inst., MA
• OSTI ID: 5298304
• Journal Information: Biotechnol. Bioeng. Symp.; (United States), Journal Name: Biotechnol. Bioeng. Symp.; (United States) Vol. 24:3; ISSN BIBSB
• Country of Publication: United States
• Language: English

Related Subjects

550700* -- Microbiology
59 BASIC BIOLOGICAL SCIENCES
ALGAE
AMIDES
BIOLOGICAL EFFECTS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CARBONIC ACID DERIVATIVES
CELL CULTURES
CHALCOGENIDES
GROWTH
NITRATES
NITROGEN COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PH VALUE
PLANTS
UREA