Carter, R. H.

Werkman, C. H.

English

Name not available

Factors Influencing the Production of Acetic Acid from Corn Stalks by Thermophilic Bacteria

University of Northern Iowa

Proceedings of the Iowa Academy of Science Volume 37 Annual Issue Article 6 1930 Factors Influencing the Production of Acetic Acid from Corn Stalks by Thermophilic Bacteria C. H. Werkman Iowa State College R. H. Carter Iowa State College Copyright ©1930 Iowa Academy of Science, Inc. Follow this and additional works at: https://scholarworks.uni.edu/pias Recommended Citation Werkman, C. H. and Carter, R. H. (1930) "Factors Influencing the Production of Acetic Acid from Corn Stalks by Thermophilic Bacteria," Proceedings of the Iowa Academy of Science, 37(1), 51-52. Available at: https://scholarworks.uni.edu/pias/vol37/iss1/6 This Research is brought to you for free and open access by the Iowa Academy of Science at UNI ScholarWorks. It has been accepted for inclusion in Proceedings of the Iowa Academy of Science by an authorized editor of UNI ScholarWorks. For more information, please contact scholarworks@uni.edu. FACTORS INFLUENCING THE PRODUCTION OF ACETIC ACID FROM CORN STALKS BY THERMOPHILIC BACTERIA c. H. WERKMAN AND R.H. CARTER Among the factors influencing the yields of acid in the thermo-philic acetic acid fermentation of corn cobs are: ( 1) hydrogen ion concentration at which the process takes place, (2) state of division of substrate, ( 3) temperature of incubation, ( 4) source of inocu-lum. The optimum pH for acid yield was found to be near 9.0 with a range of good yields from pH 8.5 to 9.5. The reduction in yields is marked below pH 8.5 and above 9.5. The pH was ad-justed daily. Using large inoculations (5% by volume) of actively growing cultures the yields of acid were greatest during the first day and showed a reduced yield on each successive day. The high alkaline fermentations showed greater yields on the first clay but showed a more marked decline on succeeding days than did the more nearly neutral- fermentations. The yields calculated as percent of acetic acid at different pH values are shown in Table I. The experiment was stopped on the 19th day when the flasks in the favorable range were showing some fermentation. The percentage yields of acid calculated as acetic per day are shown in Table II for the optimum range of pH. Some formic acid and traces of butyric were produced. The optimum temperature was found to be clo.se to 63 ° C. The maximum was 72° and below 50° the fennentation was not typical. Grinding the cobs to increase the surface area increased the rate of fermentation and the yield. Goat manure furnished a good source of inoculum although soil or other manures may be · used. No pure cultures or mixtures of pure cultures were obtained which would produce as high yields of acid as the impure mixtures obtained from manure inoculations. The efficiency of the impure culture increased upon repeated transfer. The rate of acid pro-duction increased until fermentation was complete within 7 clays. IowA STATE COLLEGE, AMES, IowA. 51 1Werkman and Carter: Factors Influencing the Production of Acetic Acid from Corn StalkPublished by UNI ScholarWorks, 1930Table I Erre:cT oF PH oN Yn:w or Acrn pH I 7.2 I 7.5 I 8.0 I 8.5 I 9.0 % Cob as acetic - 2.8-- 2.4 13.5 --zl.8-- ---z3.l No. of experiments averaged S --1--1 8 1--~ 6-- 6 9.5 20.9 4 Table II -Daily Yields 1 of Acid as Acetic in Optimum Range of pH. -DAY No. oF ExrERI- 1 I 2 3 4 5 6 7 MENTS AVERAGED PH % % % % % % % 6 8.5 3.0 2.7 2.2 2.0 1.8 0.9 0.8 6 9.0 3.4 2.5 2.7 1.5 1.6 1.3 2.0 4 9.5 3.9 2.8 2.4 2.3 1.4 1.3 0.8 1 Calculated as per cent by weight of cob. 10.0 13.9 3 8 9 % % 0.8 0.8 1.2 1.2 0.8 0.9 10.5 14.0 3 10 % 0.8 1.0 0.9 <.n N H 0 ~ :> :> () :> t:i tr> !?' ~ 0 >zj U1 () frj z 0 tr> 2Proceedings of the Iowa Academy of Science, Vol. 37 [1930], No. 1, Art. 6https://scholarworks.uni.edu/pias/vol37/iss1/6

https://scholarworks.uni.edu/cgi/viewcontent.cgi?article=5161&context=pias

Factors Influencing the Production of Acetic Acid from Corn Stalks by Thermophilic Bacteria

Abstract

Similar works

Full text

Available Versions

Name not available

University of Northern Iowa