초록
<P><B>Abstract</B></P> <P>In this study, highly reactive endo- and exo-polygalacturonases (PGs) were produced from the tobacco industry wastewater using immobilized <I>Rhizopus oryzae</I>. Compared with free cells, immobilized cells increased enzyme activity 2.8-fold and reduced production time to 24h by shake-flask production. Moreover, the immobilized cells enabled the semi-continuous production of enzymes through repeated-batch mode for seven consecutive cycles in a scale-up bioreactor. During the first five cycles, the average endo-PG and exo-PG activities reached 307.5 and 242.6U/ml, respectively. The addition of crude enzyme for the hydrolysis of pectin-containing lignocellulosic biomass under high-gravity conditions increased glucose release 4.2-fold (115.4 vs. 29.0g/L), compared with hydrolysis using cellulase alone. This process achieves the efficient production of pectin-degrading enzymes, provides a cost-effective method for tobacco wastewater treatment, and offers the possibility to obtain fermentable sugars with high-titer from pectin-containing lignocellulosic biomass, which has important potential for the commercial production of bio-fuels.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Tobacco wastewater can provide sufficient nutrients and inducers for PGs production. </LI> <LI> Production time was shortened using immobilized <I>Rhizopus oryzae.</I> </LI> <LI> Semi-continuous PGs production was achieved though repeated-batches mode. </LI> <LI> Enzyme productivity was highest among all studies reported to date. </LI> <LI> Hydrolysis by cellulase was improved by adding the crude enzyme. </LI> </UL> </P>