From tilapia (Oreochromis niloticus) farming, the by-products have been identified as a source of collagen that could be used for the development of dermocosmetics or pharmaceutical products. However, the characteristics of collagen related to a specific strain or culture must be well defined prior to its application. Collagen was extracted from the skin of three strains of tilapia: red YY males (YY: two Y-type sex chromosomes), XX gray females, and the F1: offspring of crossing red YY males with XX gray females; at different ages in the adult phase, using acetic acid and pepsin enzyme. The characteristics of acid-soluble collagen (ASC) and pepsin-soluble collagen (PSC) were shown by SDS-PAGE band profiles to be similar to bovine collagen type I (SIGMA), the PSC of gray tilapia being more fragile to temperature changes, consistent with the results of fractional viscosity. The characteristics of the F1 progeny were prioritized for being a commercially productive and sustainable source for the extraction of collagen, and the ASC form, being the one with the greatest stability and advantage over PSC, of importance to our investigations, leads to a controlled digestion as in the case of peptide induction, and also in the development of natural products in the pharmaceutical and/or dermocosmetic industry. Evaluations of the triple helix structure by FT-IR, X-ray diffraction and UV–visible spectroscopy give similar results between the strains: red, gray, and F1, and between ages in the adult form F1 (15, 24, and 36 months of age). Consequently, the skin of tilapia in adult form is recommended sustainably for up to 24 months of age where the collagen is obtained with the use of acetic acid without enzymatic treatment.
Polyhydroxyalkanoates (PHA) are biodegradable biopolymers of microbial origin that can be alternative materials to decrease the extensive use of plastics of petrochemical or synthetic origin. Thus, the selection of microorganisms with potential for PHA production from unexplored natural sources is a strategy to find bacterial species of high value. In the current study, 55 microbial strains related to bacteria were isolated from agricultural soils from Cascas, Peru. Initially, 4 strains were selected by Sudan Black B staining and Nile blue A fluorescence methods, subsequently, they were screened to examine its production capacity of PHA. Bacillus thuringiensis SP7-1 strain was selected based on its high production of PHA at 0.54 ± 0.16 g/L with an accumulation of 19 % by weight of cell biomass, during 72 h at 30 ºC. The isolate was characterized by its morphology, biochemical and molecular tests through the 16S rRNA gene. The extracted HIGHLIGHTS• Bacillus thuringiensis SP7-1 from agricultural soils producing polyhydroxyalkanoate.• The strains SP7-1 with a PHA accumulation of 0.54 g/L and 19 % in dry biomass.• PHA was characterized with FTIR, DSC and TGA with remarkable chemical properties.• A thermic degradation in a range of 270-303°C and a Melting Temperature of 166.88°C.
The effluents generated in the paper industry, such as black liquor, have a high content of lignin and other toxic components; however, they represent a source of lignin-degrading bacteria with biotechnological potential. Therefore, the present study aimed to isolate and identify lignin-degrading bacteria species in paper mill sludge. A primary isolation was carried out from samples of sludge present in environments around a paper company located in the province of Ascope (Peru). Bacteria selection was made by the degradation of Lignin Kraft as the only carbon source in a solid medium. Finally, the laccase activity (Um-L−1) of each selected bacteria was determined by oxidation of 2,2′-azinobis-(3-etilbencenotiazolina-6-sulfonate) (ABTS). Bacterial species with laccase activity were identified by molecular biology techniques. Seven species of bacteria with laccase activity and the ability to degrade lignin were identified. The bacteria Agrobacterium tumefasciens (2), Klebsiella grimontii (1), and Beijeinckia fluminensis (1) were reported for first time. K. grimowntii and B. fluminensis presented the highest laccase activity, with values of 0.319 ± 0.005 UmL−1 and 0.329 ± 0.004 UmL−1, respectively. In conclusion, paper mill sludge may represent a source of lignin-degrading bacteria with laccase activity, and they could have potential biotechnological applications.
The carotenoids have vast medical, industrial, dietary, and pharmaceutical importance due to their provitamin A precursor, immunomodulator, antioxidant and photoprotective activity. The purpose of the research was to optimize the production of carotenoids using Rhodotorula mucilaginosa from artichoke agroindustrial waste as a low-cost substrate. The artichokes bracts waste was bleached by sodium hypochlorite (NaClO 2%) and was characterized through whiteness index and FTIR. The bleached artichoke waste (BABW) used in the fermentation went through acid hydrolysis, applying 8% of the bleached artichokes residue and sulfuric acid (2.5%) for 1 h at 90°C, obtaining a greater reduced sugars content at 3.1 g/L. Rhodotorula mucilaginosa was isolated and molecularly identified. The production of carotenoids from a culture media based on hydrolyzed BABW, peptone (0.5%), yeast extract (0.1%) and sodium chloride (0.5%) was evaluated at different conditions of pH (5–8) and agitation speed (80–160 rpm) applying the surface response methodology by a rotational central compound design. The best carotenoids performance obtained had 2968.95 µg/L VVC and 1228.53 µg/g TFC at pH 5, 120 rpm and 30°C for 72 h. The chemical characterization of the extracted carotenoids was confirmed by UV-VIS and Raman spectroscopy methods. The results suggest that Rhodotorula mucilaginosa is capable of producing carotenoids from artichoke waste fermentation, providing a low-cost and sustainable alternative route for use in the global market.
Bioelectroremediation (BER) uses electrical current to stimulate catabolism of environmental pollutants, such as petroleum spills. However, applying current to soil may have adverse effects on the microorganisms involved in petroleum degradation. We identify and evaluate the BER capabilities of a strain of Aspergillus niger obtained from petroleum-contaminated soil. Spores of this strain immobilized in alginate spheres (2 g) were mixed with 100 g of hexadecane-contaminated sandy loam soil and exposed to 5, 10, or 15 mA direct current in a 200 cm3 cell with copper electrodes. Soil hexadecane concentration was measured by gas chromatography. More than 94% of hexadecane was removed from the soil within 12 days for the currents tested, and the A. niger grew to 6 x106 CFU g-1 in 15 days at 10 mA current. The maximum hexadecane degradation was achieved using a 10-mA current for 20 days, but more than 99% of the hexadecane was removed by the fifth day. These results suggest that the use of spore-containing alginate beads promotes growth and petroleum biodegradation of A. niger exposed to electrical currents. Keywords: Aspergillus, bioelectroremediation, hexadecane, petroleum, soil.
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