Improving enzyme production by solid-state cultivation in packed-bed bioreactors by changing bed porosity and airflow distribution

Cellulases are essential for the hydrolysis of lignocellulosic materials in the production of second generation ethanol. Solid-state cultivation is a process that provides high concentrations of enzymes that can be used in this hydrolysis. The objectives of this work were to produce cellulases by cultivating the fungus Myceliophthora thermophila I-1D3b in a packed bed bioreactor with sugarcane bagasse (SCB) and wheat bran (WB) as substrate and to evaluate the efficiency of the enzymatic extract in the hydrolysis of SCB in natura (BIN) and pretreated with ozone, alkali and ultrasound (BOU). The conditions for enzyme production in the bioreactor were SCB:WB at a ratio of 2.3:1 (w/w), 75 % moisture content; 45 ºC; aeration rate 240 L h-1 and 96 h. The enzyme production was evaluated by endoglucanase, xylanase, filter paper (FPU) and ?-glycosidase activities. For the application of the enzymes, a central composed response surface design with 5 repetitions of the central point was used, taking enzyme volume and hydrolysis time as factors. Such cultivation yielded the following enzymatic activities: 723 U gss-1 of endoglucanases, 2024 U gss-1 of xylanase, 12.6 U gss-1 of FPU and 41 U gss-1 of ?-glucosidase. The results of the application tests indicated the best conditions as 7.0 ml of the enzyme extract (4.2 FPU) and 6 hours for BIN and BOU. The best cellulose-glucose conversions were obtained for BOU, reaching 32.1 % at 65 ºC. In conclusion, the enzyme production in the packed bed bioreactor was efficient and BOU pretreatment improved the hydrolysis of biomass, increasing the efficiency of conversion of cellulose to glucose.

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Solid state fermentation of waste bread pieces by Aspergillus awamori: Analysing the effects of airflow rate on enzyme production in packed bed bioreactors

Food and Bioproducts Processing ◽

10.1016/j.fbp.2015.03.011 ◽

2015 ◽

Vol 95 ◽

pp. 63-75 ◽

Cited By ~ 23

Author(s):

Mehmet Melikoglu ◽

Carol Sze Ki Lin ◽

Colin Webb

Keyword(s):

Solid State ◽

Solid State Fermentation ◽

Enzyme Production ◽

Packed Bed ◽

Aspergillus Awamori ◽

Airflow Rate

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Cellulolytic Enzymes Production via Solid-State Fermentation: Effect of Pretreatment Methods on Physicochemical Characteristics of Substrate

Enzyme Research ◽

10.4061/2011/860134 ◽

2011 ◽

Vol 2011 ◽

pp. 1-10 ◽

Cited By ~ 35

Author(s):

Khushal Brijwani ◽

Praveen V. Vadlani

Keyword(s):

Enzyme Activity ◽

Solid State ◽

Solid State Fermentation ◽

Enzyme Production ◽

Physicochemical Characteristics ◽

Cellulolytic Enzymes ◽

Soybean Hulls ◽

Activity Data ◽

Bed Porosity ◽

Mild Acid

We investigated the effect of pretreatment on the physicochemical characteristics—crystallinity, bed porosity, and volumetric specific surface of soybean hulls and production of cellulolytic enzymes in solid-state fermentation of Trichoderma reesei and Aspergillus oryzae cultures. Mild acid and alkali and steam pretreatments significantly increased crystallinity and bed porosity without significant change inholocellulosic composition of substrate. Crystalline and porous steam-pretreated soybean hulls inoculated with T. reesei culture had 4 filter paper units (FPU)/g-ds, 0.6 IU/g-ds β-glucosidase, and 45 IU/g-ds endocellulase, whereas untreated hulls had 0.75 FPU/g-ds, 0.06 IU/g-ds β-glucosidase, and 7.29 IU/g-ds endocellulase enzyme activities. In A. oryzae steam-pretreated soybean hulls had 47.10 IU/g-ds endocellulase compared to 30.82 IU/g-ds in untreated soybean hulls. Generalized linear statistical model fitted to enzyme activity data showed that effects of physicochemical characteristics on enzymes production were both culture and enzyme specific. The paper shows a correlation between substrate physicochemical properties and enzyme production.

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Comparative Evaluation of Agroindustrial Byproducts for the Production of Alkaline Protease by Wild and Mutant Strains ofBacillus subtilisin Submerged and Solid State Fermentation

The Scientific World JOURNAL ◽

10.1155/2013/538067 ◽

2013 ◽

Vol 2013 ◽

pp. 1-6 ◽

Cited By ~ 9

Author(s):

Hamid Mukhtar ◽

Ikramul Haq

Keyword(s):

Bacillus Subtilis ◽

Solid State ◽

Wheat Bran ◽

Solid State Fermentation ◽

Soybean Meal ◽

Alkaline Protease ◽

Enzyme Production ◽

Enhanced Production ◽

Industrial Byproducts ◽

Agroindustrial Byproducts

The present study describes the screening of different agroindustrial byproducts for enhanced production of alkaline protease by a wild and EMS induced mutant strain ofBacillus subtilisIH-72EMS8. During submerged fermentation, different agro-industrial byproducts were tested which include defatted seed meals of rape, guar, sunflower, gluten, cotton, soybean, and gram. In addition to these meals, rice bran, wheat bran, and wheat flour were also evaluated for protease production. Of all the byproducts tested, soybean meal at a concentration of 20 g/L gave maximum production of the enzyme, that is, 5.74 ± 0.26 U/mL from wild and 11.28 ± 0.45 U/mL from mutant strain, during submerged fermentation. Different mesh sizes (coarse, medium, and fine) of the soybean meal were also evaluated, and a finely ground soybean meal (fine mesh) was found to be the best. In addition to the defatted seed meals, their alkali extracts were also tested for the production of alkaline protease byBacillus subtilis, but these were proved nonsignificant for enhanced production of the enzyme. The production of the enzyme was also studied in solid state fermentation, and different agro-industrial byproducts were also evaluated for enzyme production. Wheat bran partially replaced with guar meal was found as the best substrate for maximum enzyme production under solid state fermentation conditions.

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