RNA silencing of lactate dehydrogenase gene in Rhizopus oryzae


Research Report

J RNAi Gene Silencing (2011), 7, 443-448

doi: jrgsxx

Published online: 22 June 2011

Full Text: (pdf ~178kb)

RNA silencing of lactate dehydrogenase gene in Rhizopus oryzae

Ali Hashemi Gheinani ¥, Neda Haghayegh Jahromi ¥, Elisabeth Feuk-Lagerstedt*, Mohammad J Taherzadeh

University of Borås, School of Engineering, SE-501 90 Borås, Sweden

¥ These authors contributed equally to this work

*Correspondence toElisabeth Feuk-Lagerstedt , Email: elisabeth.feuk@hb.se, Tel: +46 33 435 4710, Fax: +46 33 435 4008

Received: 08 April 2011, Revised: 20 June 2011, Accepted: 20 June 2011

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ABSTRACT

Rhizopus oryzae is a filamentous fungus, belonging to the order Mucorales. It can ferment a wide range of carbohydrates hydrolyzed from lignocellulosic materials and even cellobiose to produce ethanol. However, R. oryzae also produces lactic acid as a major metabolite, which reduces the yield of ethanol. In this study, we show that significant reduction of lactic acid production could be achieved by short (25nt) synthetic siRNAs targeting the ldhA gene. The average yield of lactic acid production by R. oryzae during the batch fermentation process, where glucose had been used as a sole carbon source, diminished from 0.07gm/gm in wild type to 0.01gm/gm in silenced samples. In contrast, the average yield of ethanol production increased from 0.39gm/gm in wild type to 0.45gm/gm in silenced samples. These results show 85.7% (gm/gm) reduction in lactic acid production as compared with the wild type R. oryzae, while an increase of 15.4% (gm/gm) in ethanol yield.

KEYWORDS: siRNA, delivery, Rhizopus oryzaeldhA gene, lactate dehydrogenase, lactic acid, ethanol production

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