food, chemical, biotechnology, and detergent industries ( Bhunia et al., 2012 ). Proteases, which take action in breaking down reactions of proteins into their subunits, hold the major portion in food and feed industrial enzyme market, and they are
The ability of Kocuria varians to grow and produce protease when utilizing various local wastes was studied. Impact of cultivation pH on growth and enzyme production was also evaluated. Cassava waste combined with bambara nut waste (1:1) gave the best protease yield. Maximum enzyme production was attained when production medium was adjusted to pH 9. Highest protease concentration in the culture fluid was recorded at 20 h during the exponential phase of growth. The enzyme was optimally active and stable at 80 °C. Optimum pH for protease activity was at 11 with optimal stability at the alkaline range (pH 7–11) after incubation for 1 h. The enzyme was inhibited by EDTA, Hg2+, and Zn2+, but not by Pb2+, and was slightly stimulated by Cu2+. The properties of this protease make it a promising candidate for further studies and possible applications in processes involving extreme conditions of pH and temperature.
The toxic effects of cylindrospermopsin (cyanobacterial toxin) on animals have been examined extensively, but little research has focused on their effects on plants. In this study cylindrospermopsin (CYN) caused alterations of growth, soluble protein content and protease enzyme activity were studied on two aquatic plants Lemna minor and Wolffia arrhiza in short-term (5 days) experiments. For the treatments we used CYN containing crude extracts of Aphanizomenon ovalisporum (BGSD-423) and purified CYN as well. The maximal inhibitory effects on fresh weight of L. minor and W. arrhiza caused by crude extract were 60% and 54%, respectively, while the maximum inhibitory effects were 30% and 43% in the case of purified CYN at 20 μg ml−1 CYN content of culture medium. In CYN-treated plants the concentration of soluble protein showed mild increases, especially in W. arrhiza. Protease isoenzyme activity gels showed significant alterations of enzyme activities under the influence of CYN. Several isoenzymes were far more active and new ones appeared in CYN-treated plants. Treatments with cyanobacterial crude extract caused stronger effects than the purified cyanobacterial toxins used in equivalent CYN concentrations.
Cellulolytic, xylanolytic, chitinolytic and b-1,3-glucanolytic enzyme systems of species belonging to the filamentous fungal genus Trichoderma have been investigated in details and are well characterised. The ability of Trichoderma strains to produce extracellular proteases has also been known for a long time, however, the proteolytic enzyme system is relatively unknown in this genus. Fortunately, in the recent years more and more attention is focused on the research in this field. The role of Trichoderma proteases in the biological control of plant pathogenic fungi and nematodes has been demonstrated, and it is also suspected that they may be important for the competitive saprophytic ability of green mould isolates and may represent potential virulence factors of Trichoderma strains as emerging fungal pathogens of clinical importance. The aim of this review is to summarize the information available about the extracellular proteases of Trichoderma. Numerous studies are available about the extracellular proteolytic enzyme profiles of Trichoderma strains and about the effect of abiotic environmental factors on protease activities. A number of protease enzymes have been purified to homogeneity and some protease encoding genes have been cloned and characterized. These results will be reviewed and the role of Trichoderma proteases in biological control as well as their advantages and disadvantages in biotechnology will be discussed.
) [ 40 ] and flagellar co-expressed determinant (Fed) proteins [ 41 , 42 ]. Amongst the secreted proteins with a function in virulence of C. jejuni , the serine protease high-temperature requirement A (HtrA) can be added, which is involved in stress
and kinetic analysis of two protease inhibitors: nelfinavir mesylate and atazanavir
sulfate, were carried out to find their thermal stability. DSC curves of both
drugs showed exothermic transition. This observed process resulted in two
steps. Obtained apparent activation energy pointed at low stability of studied
protease inhibitors in water solutions.