Enrichment of
Activated Sludge Vitamin B^
S. SATHYANARAYANA RAO, Research Microbiologist
D. R. WASHINGTON, Assistant Professor
Environmental Engineering Division
Rensselaer Polytechnic Institute
Troy, New York
A. V. S. PRABHAKARA RAO, Research Associate
Civil Engineering Department
Stanford University
Palo Alto, California
S. C. PILLAI, Lecturer
Department of Biochemistry
Indian Institute of Science
Bangalore, India
INTRODUCTION
Although the vitamin B12 (5-6 dimethyl benzimidazole cyanocobalamin)
(1) content of activated sludge has been studied to some extent (2,3,4, 5), there
is need for further work in this direction to evaluate means of enrichment of the
vitamin B^2 content in hopes that activated sludge may serve as a commercial
source of this compound.
Rao and Srinath (4) have studied the influence of cobalt (Co) on both aerobic
and anaerobic flora and fuana found in waste treatment processes. They found
that the addition of one mg/l of Co to sewage treated in either an activated
sludge process or anaerobic fermentor, produced a 50 per cent increase in the vitamin B12 yield. It was noted, however, that the biological life in an activated
sludge process was essentially unchanged whereas the anaerobic culture showed a
decrease in activity and a much poorer effluent.
Hoover, et al, (6) studying the treatment of dairy waste, have reported the
yield of vitamin B-^ from their treatment process. No significance was given to
these data nor was the contribution of any of the organisms to the production of
the vitamin determined. Apart from this, there was no information found in the
literature in regard to the possible means of increasing the vitamin B12 content of
activated sludge.
This investigation was undertaken to evaluate means of enrichment of the vitamin B12 concentration in activated sludge. "The possibility of using additive
cultures, as well as the determination of the optimum Co concentration in the
system, was studied.
In exploring the possibility of enrichment of the vitamin B-^ yield by additive cultures, those organisms which are known to yield high concentrations of
vitamin B12 were considered. It was hoped that the test organisms to be studied
would be one of those which has been isolated from sewage. No organism was
found  to  fulfill these requirements.    As a compromise,   P. freudenreicha was
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