Page 34 - BOOK OF PROGRAM ICAGRI 2

Abstract Invited Speaker

Dr. Darwin, S.TP., M.Sc.
Environmental Biotechnology

Anaerobic Acidogenesis of Sugar and Agro-Starchy Wastes for
Biotechnological Production of Biofuel and Bioproduct:

Ethanol vs. Lactic Acid

Darwin

Department of Agricultural Engineering, Syiah Kuala University, Banda Aceh
23111, Indonesia
Email: darwin_ae@unsyiah.ac.id

Abstract : Anaerobic acidification of carbohydrates could produce various useful end-products.
Besides physicochemical parameters such as pH, alkalinity and temperature, the types of
substrate especially carbohydrate being anaerobic converted affects the end-product formation.
The current study showed that under non-controlled pH, microbial mixed cultures from
activated sludge and anaerobic sludge anaerobically generated ethanol from glucose
acidification while producing lactic acid as a bio-product from starch fermentation. This trend
was not only found in batch modes. Also, continuous chemostat operation of anaerobic sludge
resulted in the reproducible predominance of ethanol formation from glucose solution and lactic
acid production from starch. Changes of feeding regimes and substrate availability (shock load
versus continuous feeding) applied in glucose acidification under uncontrolled pH did not affect
the ethanol production as the main metabolite. Alterations in feed composition from glucose to
starch and vice versa resulted in an immediate change of metabolite formation. This is of
significance in various fermentation applications, such as industrial fermentation systems, bio-
energy and bio-product production and rumen fermentation system.

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