초록
<P>In a previous study, we reported that a double gene deletion mutant for CreA and CreB, which constitute the regulatory machinery involved in carbon catabolite repression, exhibited improved production of α-amylase compared with the wild-type strain and single <I>creA</I> or <I>creB</I> deletion mutants in <I>Aspergillus oryzae</I>. Because <I>A. oryzae</I> can also produce biomass-degrading enzymes, such as xylolytic and cellulolytic enzymes, we examined the production levels of those enzymes in deletion mutants in this study. Xylanase and β-glucosidase activities in the wild-type were hardly detected in submerged culture containing xylose as the carbon source, whereas those enzyme activities were significantly increased in the single <I>creA</I> deletion (<I>ΔcreA</I>) and double <I>creA</I> and <I>creB</I> deletion (<I>ΔcreAΔcreB</I>) mutants. In particular, the <I>ΔcreAΔcreB</I> mutant exhibited >100-fold higher xylanase and β-glucosidase activities than the wild-type. Moreover, in solid-state culture, the β-glucosidase activity of the double deletion mutant was >7-fold higher than in the wild-type. These results suggested that deletion of both <I>creA</I> and <I>creB</I> genes could also efficiently improve the production levels of biomass-degrading enzymes in <I>A. oryzae</I>.</P>