J. Inst. Brew. vol.110:3 (2004) Production of L-Lactic Acid from Spent Grain, a By-Product of Beer Production

Production of L-Lactic Acid from Spent Grain, a By-Product of Beer Production

Sho Shindo ^1,2 and Tadanori Tachibana ¹
¹ Akita Research Institute of Food and Brewing, 4-26 Arayasanuki, (Akita-city), Akita, 010-1623, Japan.
² Corresponding author. E-mail: shindo@arif.pre.akita.jp

J. Inst. Brew. 110(4), 347-351, 2004 | VIEW ARTICLE

ABSTRACT
L-lactic acid production from spent grain with immobilized lactic acid bacteria was investigated. Spent grains were liquefied by a steam explosion treatment to obtain liquefied sugar. When 1 kg of wet spent grain was treated under the 30 kg/cm² pressure for 1 min using a 5-L steam explosion reactor, 60 g of total sugar was obtained from the liquefied spent grain. Furthermore, 1.3% (w/v) of glucose, 0.4% (w/v) of xylose, and 0.1% (w/v) of arabinose were produced when the liquefied spent grain was treated with glucoamylase, cellulase, and hemicellulase enzymes. When batch L-lactic acid production was carried out by Lactobacillus rhamnosus NBRC14710, 19.0 g/L L-lactic acid was produced from the Tween 80 liquefied spent grain after 5 days. Furthermore, during repeated batch production with immobilized Lactobacillus rhamnosus NBRC14710 from Tween 80 liquefied spent grain at 37°C, the productivity of L-lactic acid was maintained at a 10 time higher level over a period of 40 days.

Key words:
Biodegradable plastic, L-lactic acid, spent grain.