Study on microbial protein and the mechanism of solid-state fermentation with periodical dynamic changes of air

The effect of different extraction and purification conditions on the microbial protein obtained from solid-state fermentation (SSF) and the effect of periodical dynamic changes of air on protein have been studied. The mechanism of solid-state fermentation with periodical dynamic changes of air is also discussed. Compared with static solid-state fermentation, periodical dynamic changes of air afford a higher protein mass; from 1 g of the fermentation microbe, 5.3 mg of the intracellular protein (an increase of 34.63%) and 9.09 mg of the extracellular protein (an increase of 17.8%) were obtained on the sixth day of fermentation. The filter paper activity and carboxymethyl cellulose activity (FPA and CMCase) of the extracellular protein are 1.739 μmol/s and 109.592 μmol/s, respectively, which represent increases of 60.1% and 21.2% over the corresponding values for static solid-state fermentation. The FPA and CMCase of the intracellular protein are 0.245 μmol/s and 6.392 μmol/s, respectively, which represent decreases of 22.2% and 38.7% over the corresponding values for static solid-state fermentation. The enzyme activity of the microbial extracellular protein in solid-state fermentation with periodical dynamic changes of air on the fifth day is nearly equal to that on the sixth day without periodical dynamic changes of air, so the period of fermentation can be shortened. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) experiments suggest that pulsating air pressure stimulation leads to a decrease in the amount of protein component with molecule mass of about 80400Da, and an increase in the amount of protein component with molecule mass of about 28520Da. Translated from Journal of Beijing University of Chemical Technology, 2006, 33(3): 42–46 [译自: 北京化工大学学报]     

A comparison between a conventional submerged culture fermenter and a new concept gas/solid fluid bed bioreactor for glutathione production

Glutathione is produced conventionally by submerged culture fermentation with yeast S. cerevisiae using L-cysteine, L-glutamate, and glycine as precursors. To obtain high glutathione concentrations, as well as high reaction rates, optimum temperature and high precursor concentrations have to be applied. Therefore, due to dilution in submerged culture, large quantities of precursor are needed. On the other hand, in solid state fermentation, increased precursor concentration is reached by the reduction of the water holdup in the fermenter. Experiments were performed to compare submerged culture fermentation in a stirred tank reactor with solid state fermentation in a gas/solid fluid bed bioreactor. In a 1.5 L stirred tank reactor the influence of temperature, substrate composition, and precursor concentration on reaction rate and maximum glutathione accumulation in the yeast cells was evaluated. A laboratory scale fluid bed fermenter of 0.15 m diameter and a pilot scale fermenter of 1.0 m diameter with 42 kg of yeast load were used to evaluate the optimum feed strategy to optimize glutathione yield with respect to precursor feed and glutathione accumulation in the yeast cells. In submerged culture, the maximum glutathione yield with respect to the precursor cysteine at maximum glutathione accumulation ranged from 4 to 8 mole %, whereas, with the gas/solid fermentation, yields of up to 40 mole % were obtained.     

Purification of Aspergillus carbonarius polygalacturonase using polymeric membranes

BACKGROUND: Microfiltration (MF: 70–450 nm) and ultrafiltration (UF: 10–500 kDa) membranes were used to eliminate carbohydrates and other non‐protein impurities from Aspergillus carbonarius culture broth containing polygalacturonase enzyme (EC 3.2.1.15) that would otherwise interfere with the purification processes and lead to enzyme loss. Further, diafiltration was attempted to improve the elimination of impurities as well as recovery of enzymes. RESULTS: MF resulted in removal of 2–25% carbohydrates with an enzyme recovery of 69–82% from the crude culture broth owing to the secondary layer formation. UF with 10 kDa membrane eliminated most of the carbohydrates (96%), phosphate salts and total acids with a recovery of 96% polygalacturonase and resulted in greater productivity. Using the above procedure, the enzyme was concentrated nearly 10‐fold while the purity improved from 4.6 to 49.4 U mg^?1 of dry matter. CONCLUSIONS: The results of this study focused on the elimination of carbohydrates and other non‐protein impurities showed that UF could be used efficiently as a primary purification step during downstream processing of microbial culture broths containing enzymes. The present approach will ensure complete elimination of non‐protein impurities thereby reducing the losses and difficulties in the subsequent purification steps. Copyright © 2008 Society of Chemical Industry     

Color,trypsin inhibitor and urease activity as it affects growth of broilers

In five experiments, the relationships among trypsin inhibitor contents, urease index and color in soybean meal (SBM), and the effects of those relationships on broiler chick performance were determined. Raw, solvent-extracted SBM was dehydrated to 2% moisture; then 0, 4, 8, 12, or 16% moisture was added and autoclaved at 120 C in sealed containers from 0 to 135 min with 15-min intervals. Urease and trypsin inhibitor contents decreased with either increasing moisture content or cooking time. With 16% added moisture, 30 min of cooking time was required to decrease urease index to an acceptable level, and 45 min was required to decrease trypsin inhibitor contents. Raw SBM autoclaved with less than 12% added moisture contained urease and trypsin-inhibitor contents that were not considered undesirable, regardless of cooking time used. Increased moisture and cooking time resulted in decreased trypsin inhibitor and urease contents, increased broiler growth, improved feed efficiency and decreased pancreas hypertrophy. Commercial SBM, containing 12 ug trypsin inhibited per mg of protein (μ/mg), a tristimulus+α (redness) color value of +3.21, and a urease index of 0.19 ΔpH, was autoclaved for 0–25 min with 5-min intervals to determine the effect of additional heat on broiler performance and SBM color. The commercial SBM, heated an additional 10 min, contained 1.77 μg trypgin inhibitor per mg of protein, a+a color value of +4.76, and urease index of 0.02 ΔpH. Broiler growth and feed efficiency were improved when the commercial SBM was heated an additional 10 min. Results of this study show that color is a good predictor of trypsin-inhibitor content and broiler chick performance. Color may be used to predict underprocessing, adequate, and overprocessing of SBM; however, trypsin inhibitor and urease index do not show the effect of overprocessing.     

Application of Cocultures of Fungal Mycelium during Solid-State Fermentation of Canola Meal for Potential Feed Application

In this study, the mono-, bi-, and tri-cultivation of Aureobasidium pullulans, Neurospora crassa, and Trichoderma reesei in solid-state fermentation were applied to improve the nutritional values of hexane extracted canola meal (HECM) along with the reduction of antinutritional factors for animal feed applications. Static fermentation trials of 50% moisture content HECM were conducted in 500 mL Erlenmeyer flasks for 168 hours at 30 °C. The results showed that fungal cultivation had positive effects on the level of protein, fiber, and, glucosinolates (GLS). Monoculture of N. crassa exhibited the highest protein level of 49%. The combination of A. pullulans and N. crassa provided the highest reduction of crude fiber, acid detergent fiber and neutral detergent fiber by 21.9%, 1.7%, and 9.1%, respectively. Bi-culture of A. pullulans and T. reesei resulted in the best GLS reduction by 81.3% (0.3 vs. 1.6 μM g⁻¹ GLS of uninoculated control). These results indicate that each fungal strain possesses different enzymatic ability and selectively can work with other fungi in synergistic relationship for better fungal conversion of canola meal.     

工业糖化酶固态发酵木薯渣制取单细胞蛋白饲料的研究

木薯是广西的主要经济作物之一,主要用于生产淀粉,其副产物木薯渣中仍残留大量淀粉,弃之会造成浪费和环境污染.本研究旨在探索一条利用木薯渣的新途径.以木薯渣为原料,利用工业糖化酶和产朊假丝酵母(Candida utilis)固态发酵,制取单细胞蛋白饲料.结果表明:通过高压灭菌预处理物料效果较好;氮源的添加量分别为:尿素3%,硫酸铵6%;通过单因素正交实验得最佳工艺条件为:糖化酶用量为4%,含水量为70%,发酵时间72 h,酵母接种量10%.粗蛋白质含量由底物的11.59%提高到产物的28.28%,提高了16.69个百分点.与其它方法比较,本方法利用工业糖化酶,发酵过程易于控制,不需要选育淀粉分解菌,使培养成本降低,具有一定的工业应用潜力.     

Optimization of Enzymatic Process Condition for Protein Enrichment,Sugar Recovery and Digestibility Improvement of Soy Flour

Soy protein is a valuable nutritional supplement for food and animal feed. While protein constitutes ~50 % of defatted soy flour (SF), it coexists with complex carbohydrates (30–35 %) which may have anti‐nutritional effects. An enzymatic process can remove the carbohydrate and produce protein‐enriched soy products. The hydrolysate with monomerized carbohydrates is valuable fermentation feedstock. In this study, Aspergillus niger and Trichoderma reesei enzymes were compared for use in the process. Effects of pH (3.2–6.4), temperature (40–60 °C), enzyme‐to‐SF ratio (0–2 ml/g) and SF loading (150–350 g/l) were evaluated for the enzymatic conversion of SF carbohydrate to reducing sugar (Y_RS) and total soluble carbohydrate (Y_TC) in the hydrolysate. Effects of these single factors and interactions between factors were investigated. Optimal pH and temperature were similar for both enzymes: pH 4.8 and 50–51 °C for Y_TC, and pH 5.1–5.2 and 48–51 °C for Y_RS. The two enzymes also gave similar protein contents in resultant soy protein concentrates, i.e., 74–75 % with 2 ml/g enzyme broth and 150 g/l SF, which were higher than the 64–68 % protein in commercial concentrates. A. niger enzyme was significantly more effective in carbohydrate conversion, achieving Y_RS = 75 % and Y_TC = 78 % with 2 ml/g enzyme and 150 g/l SF, higher than the Y_RS (30 %) and Y_TC (64 %) obtained with T. reesei enzyme. Monomerization was essentially complete in hydrolysate produced with A. niger enzyme.     

Optimization of agro‐residual medium for α‐amylase production from a hyper‐producing Bacillus subtilis KCC103 in submerged fermentation

BACKGROUND: Although submerged fermentation (SmF) is the conventional method in industry, use of low‐cost agro‐residues for α‐amylase production in SmF has not been well established. Here we optimized agro‐residue‐based medium and culture conditions for α‐amylase production in SmF using a hyper‐producing Bacillus subtilis KCC103. RESULTS: B. subtilis KCC103 produced α‐amylase in SmF by utilizing agro‐residues. Wheat bran (WB) and sunflower oil cake (SFOC) were selected as the best substrates using shake flasks. Medium containing WB (carbohydrate rich) and SFOC (rich in protein and free amino acids) at 1:1 (w/w) ratio produced high levels (90 IU mL⁻¹) of α‐amylase at 30–36 h in a shake flask. The α‐amylase yield was 14‐fold enhanced (1258 IU mL⁻¹) by optimizing process parameters and medium composition following response surface methodology in a bioreactor. The optimal conditions were: WB 1.27%, SFOC 1.42%, pH 7, 37 °C and 10–12 h. Both in shake flask and bioreactor α‐amylase synthesis was not repressed by the release of simple sugars into the medium. CONCLUSION: KCC103 with catabolite derepression and hyperproducing ability is useful for economic α‐amylase production using low‐cost agro‐residual substrates in conventional SmF. Since the production time (10–12 h) is much shorter than other strains this would improve productivity and further reduce the cost of α‐amylase production. Copyright © 2008 Society of Chemical Industry     

Potential of <Emphasis Type="Italic">Jatropha curcas</Emphasis> as a Biofuel,Animal Feed and Health Products

Jatropha curcas is a multipurpose plant with numerous attributes. It can potentially become one of the world’s key energy crops. Its seed weighs 0.53–0.86 g and the seed kernel contains 22–27% protein and 57–63% lipid indicating good nutritional value. The seeds can produce crude vegetable oil that can be transformed into high quality biodiesel. Several methods for oil extraction have been developed. In all processes, about 75% of the weight of the seed remains as a press cake containing mainly carbohydrates, protein and residual oil and is a potential source of livestock feed. The highly toxic nature of whole as well as dehulled seed meal due to the presence of high levels of shells, toxic phorbol esters and other antinutrients prevents its use in animal diet. The genetic variation among accessions from different regions of the world and rich diversity among Mexican genotypes in terms of phorbol ester content and distinct molecular profiles indicates the potential for improvement of germplasm of Jatropha through breeding programs. The extracts of Jatropha display potent cytotoxic, antitumor, anti-inflammatory and antimicrobial activities. The possibilities on the exploitation potential of this plant through various applications have been explored.     

核桃饼粕微生物发酵饲料的初步研究

微生物发酵饲料作为一种新型蛋白质饲料成为当前研究热点。试验以核桃压榨后的核桃饼粕为主要原料,混合玉米粉接种酵母菌进行固态发酵,研究发酵产物粗蛋白含量的变化情况,以期获得新型高蛋白含量的微生物发酵饲料。以粗蛋白含量为指标,通过单因素试验和正交试验确定发酵的最佳条件。结果表明,发酵最佳条件为:玉米粉和核桃饼粕配比2∶1、接种量10%、发酵时间4天、发酵温度30℃,在此条件下发酵得到的饲料粗蛋白含量达到34.26%,与未发酵的玉米粉粗蛋白含量10.78%相比,蛋白含量提高了23.48%。得出的结论有利于人们对核桃饼粕的开发利用,又为发酵植物蛋白生产高蛋白饲料研究提供基础和依据。     

Downstream Processing of Lactic Acid by Membrane-Based Solvent Extraction∗

Abstract

Lactic acid has extensive use in the food and chemical industry. About half the lactic acid used in the world is produced by fermentation of carbohydrates using lactic acid bacteria. The recovery of lactic acid from the fermentation broth is more difficult than the fermentation itself. In the present work a study of membrane-based solvent extraction as a separation unit for the continuous downstream processing of lactic acid from fermentation broth was carried out. The experiments were performed using simulated fermentation broths made of lactic acid in acetate buffer or distilled water as the feed solution. The effects of membrane material, organic carrier, and pH of the feed solution on membrane extraction efficiency were investigated. A separation degree of 35% was obtained by using a polyether-etherketone (PEEK-WC 14%) membrane with 5% trioctylamine as the organic carrier in n-heptane. The experimental results obtained with the simulated system encourage the use of membrane-based solvent extraction with a real fermentation broth.

     

Trypsin Inhibitor and Urease Activity of Soybean Meal Products from Different Countries and Impact of Trypsin Inhibitor on Ileal Amino Acid Digestibility in Pig

Trypsin inhibitor (TI) and urease activity (UA) are the most relevant quality aspects of soybean meal (SBM) for monogastric animals. This study’s objective was to determine the levels of TI and UA in SBM collected from feed mills in different countries, whether TI and UA are correlated since they are both heat-labile, and impact of TI on pig ileal amino acid digestibility. TI was 1.20–8.37 mg g⁻¹ with 36.4% samples <3 mg g⁻¹, UA was 0–0.311 ΔpH unit with 64.2% samples <0.05 ΔpH unit in 847 solvent-extracted SBM samples. TI and UA results varied by countries and world areas. By country, mean TI was highest in Germany and lowest in Philippines, mean UA was highest in India and lowest in Philippines. By world areas, mean TI was highest in Latin America and lowest in North America, UA was highest in Asia and lowest in Latin America. TI and UA results vary in different soybean products, TI ranked as raw soybeans > expeller SBM > full-fat-extruded (FFE) SBM ≥ heat-inactivated full-fat (HIFF) SBM > solvent-extracted SBM; UA ranked as raw soybeans > HIFF SBM > FFE SBM ≥ solvent-extracted SBM ≥ expeller SBM. TI was not correlated with UA in 847 solvent-extracted SBM, suggesting that UA may not be used as a surrogate indicator for TI. A diet contained 38% SBM with 8.78 mg g⁻¹ TI significantly reduced apparent ileal digestibility of amino acids and crude protein by 13.3–26.0% and 23.3% points, respectively, in cannulated pigs compared to SBM with 2.51 mg g⁻¹ TI.     

Poly(styrene‐block‐butadiene‐block‐styrene‐block‐butadiene) and poly(styrene‐block‐butadiene‐block‐methyl methacrylate) copolymers as compatibilizers in PPO–SAN blends. I. Morphology and fracture behavior

The toughness behavior of PPO–SAN blends with the modifier poly(styrene‐block‐butadiene) (SBSB) and with poly(styrene‐block‐butadiene‐block‐methyl methacrylate) copolymers (SBM) under impact loading conditions has been investigated. The observed morphology of blends compatibilized with SBM, in which the rubber phase discontinuously accumulated at the PPO–SAN interface, correlated with about 20 times higher energy dissipation up to maximum force and about seven times higher deformation capacity compared to pure PPO–SAN blends. In contrast, the fracture behavior of the SBSB‐modified blends was not as strongly dependent on the rubber content. It is especially noteworthy that although the SBM modification resulted in a strong increase in toughness of the PPO–SAN blends, no decrease in stiffness could be found with up to 15% rubber additions. The values of Young's moduli remained at the same high level of the nonmodified material. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2037–2045, 2000     

Effect of solid-state fermentation on select antinutrients and protein digestibility of cold-pressed and hexane-extracted canola meals

In this study, the effects of solid-state fermentation (SSF), including strain (Aspergillus niger NRRL 334 and A. oryzae NRRL 5590) and fermentation time (24, 48, and 72 h) on the nutritional value of cold-pressed (CP) and hexane-extracted (HE) canola meals were examined. SSF increased the protein content of both types of meals (from ~36% to ~40%) while reducing the oil content of CP meals (from ~12% to 9%). There was a significant reduction (~80%) in the phytic acid content of both types of meals after fermentation using either fungi. Overall, fermented samples showed a decrease in the total phenolic content from 2.7–3.1 to ~1.0 mg gallic acid equivalents (GAE)/g dry meal (DM) (a ~65% reduction), of which specifically the HE meal fermented with A. niger sample had the greatest decrease from 3.1 to 0.6 mg GAE/g DM (~81% reduction). Seventy-two hours of fermentation decreased the in vitro protein digestibility (IVPD) of A. oryzae fermented meals. In contrast, a shorter fermentation time (24 h) increased the IVPD for most samples as compared to the controls (from ~72%–73% to 77%–81%), with the exception of the CP meal fermented with A. niger which had similar IVPD at all fermentation times. Overall, the changes indicate that SSF using A. niger or A. oryzae can be useful to positively modify the composition of different canola meals and improve their nutritional value by significantly increasing the protein content, decreasing the levels of antinutrients, while only slightly reducing IVPD.     

苹果渣发酵生产菌体饲料蛋白的工艺条件研究

以有效微生物群（EM菌液）为发酵剂,对苹果渣进行固态发酵,生产菌体饲料蛋白。采用L27（313）正交设计试验和单因素试验对固态发酵条件进行了研究,以得到较合理的培养基。研究结果表明,苹果渣发酵的最佳培养基组成为：蔗糖添加量3%,含水量30%,培养温度25℃,接种量0.8%,发酵时间4d。发酵产物的粗蛋白含量由5.82%提高到21.28%,粗脂肪和粗灰分也有所提高,营养价值得到了改善。     

Screening and selection of microfungi for microbial biomass protein production and water reclamation from starch processing wastewater

Thirty strains of microfungi and amylolytic yeasts were screened for production of microbial biomass protein (MBP) and water reclamation from starch processing wastewater (SPW). Three species and six strains of microfungi Aspergillus oryzae, Rhizopus oligosporus and Rhizopus arrhizus showing high enzymatic activities on SWP were selected under non‐aseptic growth conditions. In 20 h submerged cultivation the selected strains had a high capacity to enzymatically hydrolyse more than 93% of the starch and produce 4.3–5.6 g dm⁻³ of dry biomass at a specific biomass growth rate from 0.05 to 0.12 h ⁻². The fungal biomass contained crude protein ranging from 37.5 to 49.8% of dry biomass. The pellet and flocculated biomass products were easily harvested by simple filtration or sedimentation. After these processes, 76–88% of total organic carbon (TOC), 85%–92% of chemical oxygen demand (COD) and 95% suspended solids in SPW were removed, and the treated water was reusable for farm irrigation. Typical pretreatment processes including hydrolysis, sterilisation and nutrient supplementation were unnecessary. © 1999 Society of Chemical Industry     

Melting and crystallization behaviors of compatibilized poly(trimethylene terephthalate)/acrylonitrile–butadiene–styrene blends

The melting and crystallization behaviors of poly(trimethylene terephthalate) (PTT)/acrylonitrile–butadiene–styrene (ABS) blends were investigated with and without epoxy or styrene–butadiene–maleic anhydride copolymer (SBM) as a reactive compatibilizer. The existence of two separate composition-dependent glass-transition temperatures (T_g's) indicated that PTT was partially miscible with ABS over the entire composition range. The melting temperature of the PTT phase in the blends was also composition dependent and shifted to lower temperatures with increasing ABS content. Both the cold crystallization temperature and T_g of the PTT phase moved to higher temperatures in the presence of compatibilizers, which indicated their compatibilization effects on the blends. A crystallization exotherm of the PTT phase was noticed for all of the PTT/ABS blends. The crystallization behaviors were completely different at low and high ABS contents. When ABS was 0–50 wt %, the crystallization process of PTT shifted slightly to higher temperatures as the ABS content was increased. When ABS was 60 wt % or greater, PTT showed fractionated crystallization. The effects of both the epoxy and SBM compatibilizers on the crystallization of PTT were content dependent. At a lower contents of 1–3 wt % epoxy or 1 wt % SBM, the crystallization was retarded, whereas at a higher content of 5 wt %, the crystallization was accelerated. The crystallization kinetics were analyzed with a modified Avrami equation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Modulated gluconic acid production from immobilized cells of Aspergillus niger ORS‐4.410 utilizing grape must

BACKGROUND: Gluconic acid (GA) production by immobilized cells of mutant Aspergillus niger ORS‐4.410 on polyurethane sponge (PUS) and calcium‐alginate (Ca‐alginate) was evaluated in repeated batches of solid state surface fermentation (SSF) and submerged fermentation (SmF) conditions, respectively, utilizing rectified grape must as carbon source. RESULTS: The passive immobilization of cells in fermentation medium solid support of having 0.4 cm³ cube size, 4% spore suspension, 0.6 g inoculum of PUS immobilized cells at 32 °C and 2.0 L min^?1 resulted in the maximum GA production (88.16 g L^?1) with a 92.8% yield, while the Ca‐alginate matrix with a 0.5 cm diameter bead size, 2–3% spore suspension, 15 g inoculum at 34 °C and 150 rpm agitation speed revealed 67.19 g L^?1 GA with a 85.2% yield. Repeated use of PUS showed higher levels of GA (110.94 g L^?1) in the third–fourth fermentation cycles with 95–98% yield and 22.50 g L^?1 d^?1 productivity under SSF that was 2.5‐fold higher than the productivity obtained from a typical fermentation cycle, and 54% greater than the productivity obtained with repetitive use of Ca‐alginate immobilized cells of A. niger under SmF. CONCLUSION: Using immobilized cells of A. niger in PUS, the rectified form of grape must can be utilized for GA production as an alternative source of carbohydrate by replacing the conventional fermentation conditions. Copyright © 2008 Society of Chemical Industry     

Exploring the potential of recovering 1‐butanol from aqueous solutions by liquid demixing upon addition of carbohydrates or salts

BACKGROUND: Fermentative production of 1‐butanol yields dilute aqueous solutions. Recovery of the butanol from these solutions is most commonly performed by energy‐intensive distillation. This work investigated the liquid‐liquid (L‐L) phase behavior of mixtures of butanol and water to explore the potential of using L‐L phase separation as a recovery possibility for 1‐butanol. The phase behavior is preferably influenced by compounds already present in the fermentation, such as carbohydrates and salts. RESULTS: The L‐L phase equilibria of butanol and water were determined in the presence of glucose, fructose, sucrose, NaCl, LiCl and CaCl₂. The aqueous and organic phase split is more pronounced in the presence of salts than in the presence of carbohydrates. Demixing is achieved with about 0.3 kg salt kg^?1 aqueous phase containing 40 g of butanol. CONCLUSION: Operation of L‐L based recovery using salts or carbohydrates requires extreme concentrations of those compounds. For feed material containing 40 g kg^?1 butanol, the tested carbohydrates do not influence the phase equilibria sufficiently to allow butanol separation. Fermentative butanol concentrations up to 70 g kg^?1 are required to create an effective L‐L phase split. The remaining residual aqueous carbohydrate solution might be used as feed for a following fermentation. Copyright © 2011 Society of Chemical Industry     

Pectinase enzyme-complex production by Aspergillus spp. in solid-state fermentation: A comparative study

A comparative evaluation of three Aspergillus species according to their pectinase production in solid-state fermentation was performed. Solid-state fermentation offers several potential advantages for enzyme production by fungal strains. Utilization of agricultural by-products as low-cost substrates for microbial enzyme production resulted in an economical and promising process. The pectinolytic enzyme activities of two Aspergillus sojae strains were compared to a known producer, Aspergillus niger IMI 91881, and to A. sojae ATCC 20235, which was re-classified as Aspergillus oryzae. Evaluation of polymethylgalacturonase and polygalacturonase activity was performed as well as exo- vs. endo-enzyme activity in the crude pectinase enzyme-complex of the mentioned strains. Furthermore, a plate diffusion assay was applied to determine the presence and action of proteases in the crude extracts. A. sojae ATCC 20235 with highest polymethylgalacturonase activity and highest polygalacturonase activity both exo- and endo-enzyme activity, is a promising candidate for industrial pectinase production, a group of enzymes with high commercial value, in solid-state fermentation processes. Beside the enzymatic assays a protein profile of each strain is given by SDS-PAGE electrophoresis and in addition species-specific zymograms for pectinolytic enzymes were observed, revealing the differences in protein pattern of the A. sojae strains to the re-classified A. oryzae.