30
RICE UNIVERSITY STUDIES
probably negating any obligate parasitic or pathogenic mechanism. It would
appear then that algae support a select bacterial flora by excreting or-
ganic bacterial nutrients and that metabolite excretion is not an induced
response caused by the presence of bacteria.
Organic compounds present in axenic algal culture filtrates were separat-
ed and identified (Table 2). A variety of organic acids and amino acids
TABLE 2.
Extracellular products of Chlorella pyrenoidosa TX7I105
present in axenic culture filtrates
(Ward and Moyer, 1966)
|
Organic acids |
Amino acids |
Other |
|
Fumaric |
Aspartic |
PoIysaccharides |
|
Lactic |
Glutamic |
Short peptides |
|
Glycolic |
Serine |
Nucleic acids |
|
Oxalic |
Threonine |
Ammonia |
|
Pyruvic |
Isoleucine | |
|
α-ketoglutaric |
Leucine | |
|
Oxalacetic |
Tyrostne | |
|
Ascorbic |
Phenylalanine | |
|
Gluconic |
Lysine | |
|
Galacturonic |
Proline | |
|
Alanine | ||
|
Glycine | ||
|
Cystine | ||
|
Valine | ||
|
Histidine | ||
|
Ornithine |
were found that are known to serve as sources of carbon and energy for
bacterial growth. Utilization of algal excretory products was studied using
four bacteria growing singly and in combination in axenic culture filtrates