Effect of Light on the Growth and Acid Protease Production of <i>Aspergillus oryzae</i>

Abstract

Aspergillus oryzae is known to have remarkable potential for the production of secreted enzymes. Submerged (Smf) and solid-state fermentation (SSF) are optimized with regard to temperature, pH, moisture, fermentation time, inoculum concentration, etc. Besides these parameters, the effect of light on growth and its role as a bioprocess variable in controlling enzyme production in A. oryzae is pivotal and hence the subject of study. A. oryzae was shown to be susceptible to light; growth was affected and the vegetative phase of the fungus was retarded. Biochemical alterations in biomass, growth diameter, chitin, and conidiation were also observed. The acid protease production by Smf and SSF showed improvement when incubated under darkness. Our study demonstrates for the first time that light must be considered as a bioprocess variable, as certain strains of A. oryzae are sensitive to light. Moreover, total darkness could be effectively employed in protease production on a pilot scale.

Inhibition of Aspergillus oryzae Mycelium Growth and Conidium Production by Irradiation with Light at Different Wavelengths and Intensities

“…Based on the monochromatic light sources, our results could bring some thoughts on the previous studies, which used white light sources as research means. The repression in our study is similar to the light response of A. oryzae RIB40 and F6, which produced fewer conidia under a continued white fluorescent light irradiation ( 6 , 17 , 19 ); this may because white light includes the spectrum range of blue light. Besides, the light response of A. oryzae GDMCC 3.31 was not the same as that of the other A. oryzae strains.…”

“… A. oryzae F6, which was obtained after mutagenesis by UV light, formed ring-shaped colonies under the condition of 12 h of light/12 h of dark. In addition, its number of conidia and acid protease were also repressed by continuous white light at an intensity of 25 μmol photon m −2 s −1 ( 19 ). Ten laboratory A. oryzae strains were placed individually under a fluorescent lamp at a light intensity of 25 μmol photon m −2 s −1 .…”

Lighting Conditions Influence the Dynamics of Protease Synthesis and Proteasomal Activity in the White Rot Fungus Cerrena unicolor

“…A direct influence of light on acid protease activity has been reported previously for C. unicolor , Phlebia lindtneri and Pycnoporus sanquineus [ 36 ]. In Aspergillus oryzae cells, proteolytic activity showed sensitivity to light and production of respective enzymes was increased in darkness [ 37 ]. It was also found that darkness and constant lighting conditions significantly modified the activity of acid, neutral and alkaline proteases produced by N. crassa [ 38 ].…”

Deproteinization: an integrated-solution approach to increase efficiency in β-galactosidase production using cheese whey powder (CWP) solution

“…These same mediums showed that when deproteinization was not inserted previously during the preparation of the culture medium (via protein isoelectric point and continuous flow autoclave process), the enzyme activity significantly decreased to below 85%. Interestingly, Aspergillus oryzae has a known capacity to induce proteases, and consequently can provide amino acids for energy functions (Murthy et al, 2015). Thus, the absence of chemical energy Leandro Freire dos Santos et al from proteins due to the insertion of the deproteinization procedure has promoted high β-galactosidase induction to maintain the energy requirements.…”

“…Recently, Aspergillus oryzae was evaluated for its ability to induce proteases which could consequently provide amino acids for energy functions (Murthy et al, 2015). Thus, in view of the importance of obtaining β-galactosidase mainly by the induction method (high yields), it was hypothesized that the deproteinization of cheese whey could promote high β-galactosidase induction in order to maintain the chemical energy levels which were previously provided by proteins.…”