Model
Digital Document
Publisher
Florida Atlantic University
Description
Selected species of marine filamentous fungi, Halosphaeria
mediosetigera, Humicola alopallonella, Culcitalna achraspora and
Orbimyces spectabilis, grown in a semi-synthetic medium containing
glucose 0.5, ammonium nitrate 0.24, tris(hydroxyrnethyl)aminomethane
0.12 and yeast extract 0.1% (Medium A) and modifications thereof
have been studied with regard to cellular composition, carbon fate
and growth kinetics. Cultures were aerated with sterile, carbon
dioxide-free air and washed mycelia were analyzed for macroconstituent
elementary composition, total carbon, protein, chitin and
lipids. Culture filtrates were tested for total carbon, .extracellular
carbohydrates and organic acids. Physiological profiles
were obtained to ascertain and correlate the ·extent and rate of
growth; and changes in pH, concentration of glucose . and anthronepositive
materials. · Elementary analyses of washed fungal mycelia
showed 41.0 to 49.0% carbon, 4.7 to 6.0% nitrogen and 5.4 to 6.5% ·
hydrogen. Optimal growth was accompanied by a concomitant fall in
pH followed by a shift back to the alkaline side. Following autolysis
at 8 days, almost one-third of the glucose substrate reappeared in
the medium accompanied by smaller amounts of mannose with Halosphaeria.
With Culcitalna, following exhaustion of glucose in the medium,
autolysis was accompanied by the reappearance of glucose. Pentoses
and a hexose other than glucose also were indicated by relative
mobilities on thin layer chromatograms. The most profound pH changes
were obtained with Humicola reaching a low of 2.4 in 15 days, but
the pH at 45 days had stabilized around 5.3. Increasing the glucose concentration to 5.0% (Medium B) did not increase the mycelial
yields to any substantial degree except for Halosphaeria. In
all cases pH fluctuated around 4 between 10 and 25 days, hut the final
pH was about 6. Production of mycelia was always accompanied by
substantial utilization of the glucose in the medium. When the
glucose concentration was raised to 5%, to force the buildup of
metabolic products, and yeast extract omitted (Medium C), substantial
amounts of glucose were utilized, but this was not manifested by
parallel increases in growth. Carbon balance studies confirmed that
pH changes were not due to the production of organic acids, but
probably to preferential utilization of ailllllonium cations. The initial
substrate carbon was found almost exclusively in the fungal mycelia
and evolved carbon dioxide. Carbon recoveries obtained under standard
conditions were 97.9, 97.4, 98.2 and 94.0% respectively for
Halosphaeria mediosetigera, Humicola alopallonella, Culcitalna
achraspora and Orbimyces spectabilis in the standard medium containing
0.5% glucose. In 5% glucose (Medium B) the recoveries were 93.0,
90.6 and 84.7% for the first three organisms mentioned. Time did
not allow a complete investigation of the causes. of decreased carbon
recoveries, but greater production of incompletely oxidized metabolites
appeared probable. Economic coefficients were determined for three
species in three media while determinations on the fourth species are
in progress. Culcitalna gave values of 71 in Medium A, 40 in Medium B
and 3 in Medium C; Halosphaeria gave 78 in A, 45 in B and 15 in C;
Orbimyces gave 75 in A and 7 in C . The effect of omission of yeast extract and of elevated glucose concentration on the economic
coeffic ients was pronounced . The only products detected under exaggerated
carbon conditions were acetic acid in the culture broth of Culcitalna
and a greenish pigment in the culture filtrate of Halospaeria. The
analogously-suggested accumulation of 2-ketogluconic acid in the latter
case could be indicative of the functioning of the hexose monophosphate
shunt or another primary aerobic pathway.
mediosetigera, Humicola alopallonella, Culcitalna achraspora and
Orbimyces spectabilis, grown in a semi-synthetic medium containing
glucose 0.5, ammonium nitrate 0.24, tris(hydroxyrnethyl)aminomethane
0.12 and yeast extract 0.1% (Medium A) and modifications thereof
have been studied with regard to cellular composition, carbon fate
and growth kinetics. Cultures were aerated with sterile, carbon
dioxide-free air and washed mycelia were analyzed for macroconstituent
elementary composition, total carbon, protein, chitin and
lipids. Culture filtrates were tested for total carbon, .extracellular
carbohydrates and organic acids. Physiological profiles
were obtained to ascertain and correlate the ·extent and rate of
growth; and changes in pH, concentration of glucose . and anthronepositive
materials. · Elementary analyses of washed fungal mycelia
showed 41.0 to 49.0% carbon, 4.7 to 6.0% nitrogen and 5.4 to 6.5% ·
hydrogen. Optimal growth was accompanied by a concomitant fall in
pH followed by a shift back to the alkaline side. Following autolysis
at 8 days, almost one-third of the glucose substrate reappeared in
the medium accompanied by smaller amounts of mannose with Halosphaeria.
With Culcitalna, following exhaustion of glucose in the medium,
autolysis was accompanied by the reappearance of glucose. Pentoses
and a hexose other than glucose also were indicated by relative
mobilities on thin layer chromatograms. The most profound pH changes
were obtained with Humicola reaching a low of 2.4 in 15 days, but
the pH at 45 days had stabilized around 5.3. Increasing the glucose concentration to 5.0% (Medium B) did not increase the mycelial
yields to any substantial degree except for Halosphaeria. In
all cases pH fluctuated around 4 between 10 and 25 days, hut the final
pH was about 6. Production of mycelia was always accompanied by
substantial utilization of the glucose in the medium. When the
glucose concentration was raised to 5%, to force the buildup of
metabolic products, and yeast extract omitted (Medium C), substantial
amounts of glucose were utilized, but this was not manifested by
parallel increases in growth. Carbon balance studies confirmed that
pH changes were not due to the production of organic acids, but
probably to preferential utilization of ailllllonium cations. The initial
substrate carbon was found almost exclusively in the fungal mycelia
and evolved carbon dioxide. Carbon recoveries obtained under standard
conditions were 97.9, 97.4, 98.2 and 94.0% respectively for
Halosphaeria mediosetigera, Humicola alopallonella, Culcitalna
achraspora and Orbimyces spectabilis in the standard medium containing
0.5% glucose. In 5% glucose (Medium B) the recoveries were 93.0,
90.6 and 84.7% for the first three organisms mentioned. Time did
not allow a complete investigation of the causes. of decreased carbon
recoveries, but greater production of incompletely oxidized metabolites
appeared probable. Economic coefficients were determined for three
species in three media while determinations on the fourth species are
in progress. Culcitalna gave values of 71 in Medium A, 40 in Medium B
and 3 in Medium C; Halosphaeria gave 78 in A, 45 in B and 15 in C;
Orbimyces gave 75 in A and 7 in C . The effect of omission of yeast extract and of elevated glucose concentration on the economic
coeffic ients was pronounced . The only products detected under exaggerated
carbon conditions were acetic acid in the culture broth of Culcitalna
and a greenish pigment in the culture filtrate of Halospaeria. The
analogously-suggested accumulation of 2-ketogluconic acid in the latter
case could be indicative of the functioning of the hexose monophosphate
shunt or another primary aerobic pathway.
Member of