Control of agitation rate and aeration for enhanced polygalacturonase production in submerged fermentation by Aspergillus sojae using agro-industrial wastes

FRATEBIANCHI DE LA PARRA, DANTE; CRESPO, JUAN MANUEL; TARI, CANAN; CAVALITTO, SEBASTIÁN FERNANDO

JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY

JOHN WILEY & SONS LTD

Lugar: LOndres; Año: 2017 vol. 92 p. 305 - 310

0268-2575

BACKGROUND: The koji mold Aspergillus sojae, an industrially important microorganism, canproduce high levels of pectinases utilizing agro-industrial wastes. This studyintroduces apricot and peach pomace, two agro-industrial wastes barelyconsidered as raw material for the generation of value?added products, andfocuses on its utilization together with orange peel for polygalacturonase productionin submerged cultures using A. sojae.RESULTS: A Doehlert response surface methodologydesign conducted in shake flasks and applied individually with these threeby-products led to 60 ? 80 U/ml polygalacturonase activity. In bioreactorstudies performed with a mixture of apricot pomace and orange peel, by fixingstirrer speed to 600 rpm and cascading airflow to the dissolved oxygen tensionup to 1.7 vvm, oxygen limitation problems were overcome and polygalacturonaseactivity values of 380 U/ml were achieved.CONCLUSION: A simple and efficient strategy to minimizeoxygen limitation with the lowest possible shear stress is provided forstirred-tank bioreactors working with highly viscous broths, so as toultimately enhance microbial enzyme production. The polygalacturonase activityyields obtained in our study are among the highest reported in the literature.