Five protease-producing and non-mycotoxin-producing fungi (
Mucor subtilissimus
URM 4133,
Mucor
sp. URM 4146,
Mucor guilliermondii
URM 5848,
Aspergillus viride-nutans
URM 6629 and
Penicillium ...decumbens
URM 6018) were used for hydrolysis of caprine casein. Peptides obtained from different fungi were separated on two fractions: molecular mass (MM) < 3 kDa and MM from 3 to 10 kDa, and the peptide fractions were investigated for antimicrobial, antioxidant and antihypertensive bioactive properties. All the 3 to 10 kDa fractions of all fungi were able to inhibit the growth of the three Gram-negative bacteria and the hydrolysate from URM 5848 inhibited all bacteria, except the bacteria Gram-positive
Enterococcus faecalis
. All hydrolysates with the peptides between 3 and 10 kDa possessed a strong scavenging capacity for ABTS
•+
2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals, in which URM 5848 (100% and 32%) and URM 4133 (99% and 29%), respectively for (ABTS
•+
and DPPH) were the best hydrolysates. The antihypertensive activity was only observed for hydrolysates from the URM 5848 and URM 4133 fungi, and the higher inhibitory effect was observed on fractions < 3 kDa with URM 5848, 19% and URM 4133, 16%. This work was successful in demonstrating the hydrolysates from goat casein by selected fungal proteases are effective in producing different bioactive peptides.
This study aimed to select endophytic fungi to produce L-asparaginase and partially optimising the production of the enzyme using cacti as substrate. Seventeen endophytes were assessed for ...intracellular enzymatic potential in modified Czapek Dox’s medium using L-proline as an inducer. The best producer was evaluated for intracellular and extracellular enzymatic activity in modified Czapek Dox’s medium using flours of
Opuntia ficus-indica
and
Nopalea cochenillifera
as substrate. The biomass and L-asparaginase production profile was analysed and the best conditions for enzyme production were verified using factorial design.
Penicillium decaturense
URM 7966,
Diaporthe ueckerae
URM 8321, and
Colletotrichum annellatum
URM 8538 produced 0.76 U g
− 1
, 0.87 U g
− 1
, and 0.74 U g
− 1
L-asparaginase, respectively.
Diaporthe ueckerae
URM 8321 produced only intracellular L-asparaginase, using flours of
N. cochenillifera
(0.72 U g
− 1
) and
O. ficus-indica
(0.90 U g
− 1
) and the last was selected for the next steps. The ideal time for biomass and L-asparaginase production was 120 h. The best conditions for enzyme production (1.67 U g
− 1
) were initial pH 4.0, inoculum concentration 1% and cacti flour concentration 0.2%; where was observed an increase of 46.11% in compared to the initial production.
Opuntia ficus-indica
flour is indicated as an alternative low-cost substrate for the production of L-asparaginase by the endophytic fungus
D. ueckerae
URM 8321.
Acremonium sp. L1-4B isolated from lichen in Antarctica was used to produce extracellular proteases through submerged fermentation using cactus pear extract (Opuntia ficus-indica Mill.). A 23 ...factorial design was applied to optimize the protease production using three independent variables, namely temperature, pH and concentration of yeast extract, was also used a Central Composite Design (CCD) under Response Surface Methodology (RSM). All variables and interactions analyzed in the factorial design were significant or marginally significant, a Central Composite Design was developed, and the Response Surface Methodology towards the highest point it was established. The experimental model was validated under 14°C, pH 7.54, and 0.55% yeast extract, showing a protease activity of 447.65±2.6U/mL by a prediction model of 445.48U/mL. The enzyme showed a molecular weight of 59kDa; it was inhibited in the presence of PMSF (serine protease); it presented optimal conditions at pH 8.0 and 50°C; it remained stable at pH in the 3.0–9.0 range and between 10 and 40°C; it showed a tolerance to 3000mM NaCl as well as to surfactants, hydrogen peroxide and urea at 5%. This paper presents a proposal for an economically attractive production methodology using cactus pear as a primary source of carbon. In addition, the protease secreted by Acremonium sp. L1-4B presented a combination of biochemical characteristics that grants a promising variability of biotechnological applications.
Display omitted
•Attractive method proposal on cactus pear biotransformation.•Feasibility of agricultural products use in bioprocesses.•Cold-active protease secreted by filamentous fungus isolated in Antarctica.•Different NaCl and surfactants concentrations tolerant biocatalyst.•Serino protease stable on all evaluated pH ranges.
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