Controlling filamentous fungi morphology with microparticles to enhanced ß-mannanase production.

ß-mannanase was produced mainly by Aspergillus species and can degrade the ß-1,4-mannose linkages of galactomannans. This study was undertaken to enhance mannanase production using talcum and aluminum oxide as the microparticles, which control cell morphology of recombinant Aspergillus sojae in glucose and carob extract medium. Both microparticles improved fungal growth in glucose and carob pod extract medium. Aluminum oxide (1 g/L) was the best agent for glucose medium which resulted in 514.0 U/ml. However, the highest mannanase activity was found as 568.7 U/ml with 5 g/L of talcum in carob extract medium. Increase in microparticle concentration resulted in decreasing the pellet size diameter. Furthermore, more than 10 g/L of talcum addition changed the filamentous fungi growth type from pellet to pellet/mycelium mixture. Results showed that right type and concentration of microparticle in fermentation media improved the mannanase activity and production rate by controlling the growth morphology.

Inulinase and fructooligosaccharide production from carob using Aspergillus niger A42 (ATCC 204447) under solid-state fermentation conditions.

This study aimed to the production of inulinase and fructooligosaccharides (FOSs) from carob under the solid-state fermentation (SSF) conditions by using Plackett-Burman Design (PBD). Based on the results the maximum inulinase and specific inulinase activities were 249.98 U/mL and 318.29 U/mg protein, respectively. When the fructooligosaccharide (FOS) results were evaluated, the maximum values of 1,1,1-Kestopentaose, 1,1-Kestotetraose, and 1-Kestose were 182.01, 506.16, 132.16 ppm while the lowest and highest total FOS values were 179.35 and 516.66 ppm, respectively. On the other hand, it was observed that the maximum inulinase activity was found at the center points of the design. Therefore, validation fermentations were carried out at center point conditions. Subsequently, the yielded bulk enzyme extracts were partially purified using Spin-X UF membranes with 10, 30, and 50 kDa cut-off values. After purification, the maximum inulinase activity was 247.30 U/mg using a 50 kDa cut-off value. Followed by this process, the purified enzyme was used to produce FOSs and the results indicated that the maximum total FOS amount was 28,712.70 ppm. Consequently, this study successfully demonstrates that Aspergillus niger A42 inulinase produced from carob under the SSF conditions can be used in FOSs production.

Growth control agent for filamentous fungi: FDM based 3D printed cubes for suspended Aspergillus sojae fermentation.

The main problem for submerged fermentation of filamentous fungi is the nutrition limitation with high cell density or cell leakage by the uncontrollable hyphae, clusters, or pellets. There are several techniques such as microparticle, immobilization, pH shifting, substrate limitation etc. for controlling filamentous fungi growth on submerged fermentation. In this research, FDM (Fused Deposition Modelling) based 3D printed cubes is used for growth control agent of recombinant Aspergillus sojae for the first time. Lattice structure sizes, number of cubes and pH were chosen to be main factors of fermentation in order to study the combine effect of the factors on A. sojae fermentation. The results revealed that specific activity values are improved from 2045.96 U/mg (the highest control activity) to 3291.67 U/mg with lower pellet sizes and controllable growth. FDM based 3D printed cubes was successfully controlled the recombinant Aspergillus sojae fermentation and enhanced ß-mannanase production. In addition, this research was also showed that FDM based 3D printed cubes also have the potential to be used as immobilization materials like SLS based 3D printed products in further research.

Effect of different fermentation strategies on ß-mannanase production in fed-batch bioreactor system.

Mannanases, one of the important enzyme group for industry, are produced by numerous filamentous fungi, especially Aspergillus species with different fermentation methods. The aim of this study was to show the best fermentation method of ß-mannanase production for fungal growth in fermenter. Therefore, different fermentation strategies in fed-batch fermentation (suspended, immobilized cell, biofilm and microparticle-enhanced bioreactor) were applied for ß-mannanase production from glucose medium (GM) and carob extract medium (CEM) by using recombinant Aspergillus sojae. The highest ß-mannanase activities were obtained from microparticle-enhanced bioreactor strategy. It was found to be 347.47 U/mL by adding 10 g/L of Al2O3 to GM and 439.13 U/mL by adding 1 g/L of talcum into CEM. The maximum ß-mannanase activities for suspended, immobilization, and biofilm reactor remained at 72.55 U/mL in GM, 148.81 U/mL in CEM, and 194.09 U/mL in GM, respectively. The reason for that is the excessive, and irregular shaped growth and bulk formation, inadequate oxygen transfer or substrate diffusion in bioreactor. Consequently, the enzyme activity was significantly enhanced by addition of microparticles compared to other fed-batch fermentation strategies. Also, repeatable ß-mannanase activities were obtained by controlling of the cell morphology by adding microparticle inside the fermenter.

Ultrasound-assisted dilute acid hydrolysis of tea processing waste for production of fermentable sugar.

Lignocellulosic materials that are the most abundant plant biomass in the world have the potential to become sustainable sources of the produced value added products. Tea processing waste (TPW) is a good lignocellulosic source to produce the value added products from fermentable sugars (FSs). Therefore, the present study is undertaken to produce FSs by using ultrasound-assisted dilute acid (UADA) and dilute acid (DA) hydrolysis of TPW followed by enzymatic hydrolysis. UADA hydrolysis of TPW was optimized by response surface methodology (RSM) at maximum power (900 W) for 2 h. The optimum conditions were determined as 50°C, 1:6 (w/v) solid:liquid ratio, and 1% (w/v) DA concentration, which yielded 20.34 g/L FS concentration. Furthermore, its DA hydrolysis was also optimized by using RSM for comparison and the optimized conditions were found as 120°C, 1:8 solid:liquid ratio, and 1% acid concentration, which produced 25.3 g/L FS yield. Even though the produced sugars with UADA hydrolysis are slightly less, but it can provide significant cost saving due to the lower temperature requirement and less liquid consumption. Besides, enzymatic hydrolysis applied after pretreatments of TPW were very more economic than the conventional enzymatic hydrolysis in the literature due to shorter time requiring. In conclusion, ultrasound-assisted is a promising technology that can be successfully applied for hydrolysis of biomass and can be an alternative to the other hydrolysis procedures and also TPW can be considered as suitable carbon source for the production of value-added products like biofuels, organic acids, and polysaccharides. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:393-403, 2016.