Introduction: The role of mannanases in the paper and pulp industry is well established and recently they have found application in the food and feed technology, fruit juice clarification, fruit maseration, oil drilling and detergent industry. Mannanases are mostly extracellular enzymes hydrolysing the 1,4-β-D-mannosidic linkages in mannans, galactomannans, glucomannans and galactoglucomannans.  Mannanase are enzymes produced mainly from microorganisms but mannanases produced from plants has also been reported.  However, microbes are the most potent producers of mannanase and represent the preferred source of enzymes in view of their rapid growth, limited spaces required for cultivation, and ready accessibility to genetic manipulation. Microbial mannanase have become biotechnologically importance since they target the hydrolysis of complex polysaccharides of plant tissues into simple molecules like manno-oligosaccharides and mannoses. Filamentous fungi such as recombinant Aspergillus sojae is important biocatalyst for industrial production of mannanase enzymes. But, there are some problems during the fermentation process such as limited oxygen, substrate transfer, high broth medium viscosity, excessive biomass. Because microparticles caused a change of growth morphology from pellets (thickness of biomass layer) to single hyphae. Therefore, mannanase enzyme productivity could be considerable high.

In the literature, mannanase production from different carbon source such as glucose, sucrose, molasses, and carob pod extract were performed by recombinant Aspergillus sojae without any separation and purification process and mannanase

activities were found to be 453.72 U/ml, 413.11 U/ml, 482 U/ml, and 350.82 U/ml, respectively. Besides, different quantities (0.5%, 0.75%, 1%) of nitrogen sources (yeast extract, beef extract, ammonium nitrate) were used to produce of mannanase by recombinant Aspergillus sojae in carob pod extract. And, the maximum mannanase activity was determined to be 695.6 U/ml with 0.5% ammonium nitrate.

Methods : In the present study, different concentrations of microparticles (1, 5, 10 g/L of aluminum oxide) in fermentation medium were used not only to enhance mannanase activity but also to control of morphology in recombinant Aspergillus sojae. This study was performed with fed-batch fermentation and conditions were 4% of initial sugar concentration, 200-600 rpm agitation rate (speed was gradually increased), 1% of inoculation rate, 1vvm aeration rate, pH 5 and 30ºC.

Results : The results showed that the maximum mannanase activity was determined to be 744.7 U/ml with using 5 g/L of aluminum oxide.

Discussion & Conclusions : Overall, this study demonstrated that the microparticles can be successfully implemented to enhance enzyme activity.

Acknowledgements : This study was supported by the TUBITAK foundation (Project number: 112 O 167).