A Comparative Study of New Aspergillus Strains for Proteolytic Enzymes Production by Solid State Fermentation

Abstract

A comparative study of the proteolytic enzymes production using twelve Aspergillus strains previously unused for this purpose was performed by solid state fermentation. A semiquantitative and quantitative evaluation of proteolytic activity were carried out using crude enzymatic extracts obtained from the fermentation cultures, finding seven strains with high and intermediate level of protease activity. Biochemical, thermodynamics, and kinetics features such as optimum pH and temperature values, thermal stability, activation energy (E a), quotient energy (Q 10), K m, and V max were studied in four enzymatic extracts from the selected strains that showed the highest productivity. Additionally, these strains were evaluated by zymogram analysis obtaining protease profiles with a wide range of molecular weight for each sample. From these four strains with the highest productivity, the proteolytic extract of A. sojae ATCC 20235 was shown to be an appropriate biocatalyst for hydrolysis of casein and gelatin substrates, increasing its antioxidant activities in 35% and 125%, respectively.

Partial purification and characterization of serine protease produced through fermentation of organic municipal solid wastes by Serratia marcescens A3 and Pseudomonas putida A2

“…The values of V max , K m , K cat , and K cat /K m measured for the partially purified protease were summarized in Table 1. The K m value of an enzyme indicates the affinity of the enzyme for its substrate: a low value of this parameter indicates a higher affinity [36]. It was observed that purified protease of S. marcescens had high affinity for its substrate compare to the purified protease of P. putida with K m value 0.3 and 0.5 mg/ml, respectively.…”

“…The activation energy (E a ) of protease was determined by using azocasein as a substrate at several temperatures ranging from 20 to 40 °C. The E a was calculated from the slope of linear Arrhenius plot (1) of ln [Protease Activity] versus 1/T, where E a = −slope × R, R (gas constant) = 8.314 J/K/mole, and T is the absolute temperature in Kelvin (K) [36], [44].ln(protease activity)=()-EaR×1T+lnA…”

Comparative Evaluation of in Vitro Virulence of Mould Isolates from Clinical Cases and from Air Samples and Their Mortality Rates in Galleria mellonella Larvae

“…Plaklar 37°C'de 24 saat bekletilmiş, koloni etrafındaki şeffaf zon varlığı kazeinaz aktivitesi olarak değerlendirilmiştir (8) . Fosfolipaz üretimi yumurta sarılı Sabouraud Dekstroz Agar (SDA, Difco) besiyerinde (13.0 g; NaCl (Sigma), 11.7 g; CaCl 2 (Sigma), 0.11 g; and %10 steril egg yolk emülsüyonu (Sigma), 184 mL of distile su) incelenmiştir.…”

“…Her kökenden serum fizyolojik (SF) içinde hazırlanan süspansiyon 5x10 8 hücre içerecek şekilde sulandırılmıştır. Süspansiyondan 10 µl Hamilton enjektörü içine alınmıştır.…”

Effect of Novel Engineered Aspergillus oryzae on Soybean Meal Fermentation and Optimization of Cultivation Conditions

“…A. oryzae mainly secretes neutral protease, with relatively low alkaline protease and acid protease activities, thus, presenting low degradation and utilization of raw protein (Zhao et al, 2014). To meet the needs of the fermentation industry, researchers are committed to develop new A. oryzae strains with high protease activity to improve raw protein utilization and composition of fermentation products (Ortiz et al, 2016;Xu et al, 2011;Fang et al, 2009). Genetic engineering has been reported to significantly enhance the protease activity of A. oryzae (te Biesebeke et al, 2005;Hunter et al, 2013;Olempska-Beer et al, 2006).…”