Denise Castro-Ochoa

Lipases and cutinases have had different applications in the food and textile industries, fuel production, and recently in processes that help the environment, such as plastic degradation. Biotechnological alternatives have been proposed to mitigate plastic residues, such as the production of biodegradable bioplastics that are based on biological and renewable resources and the biodegradation using enzymes capable of carrying out the depolymerization process, where cutinases and lipases from phytopathogenic and saprobic fungi play an important role.

Bacteria adapted to elevated temperatures are commonly associated with geothermal environments and are recognized for their functional diversity. In this study, cultivable bacteria were isolated from a geothermal spring in northern Sinaloa, Mexico, and characterized through physicochemical analysis, molecular identification, growth kinetics, and functional screening. The isolates were identified as Bacillus licheniformis (strains J1, J3, and J8) and Brevibacillus borstelensis (strains J6 and J9). Growth analyses showed that, in nutrient broth at 45 °C, the evaluated strains exhibited specific growth rates ranging from 1.25 to 1.78 h⁻¹ and short doubling times between 23 and 33 min, with B. borstelensis J6 displaying the highest rate. At 50 °C, μmax values ranged from 0.77 to 1.08 h⁻¹, indicating sustained growth at elevated temperatures. Functional assays demonstrated extracellular proteolytic, amylolytic, and cellulolytic activities, mainly associated with B. licheniformis strains, in addition to tolerance to the pesticides fluazinam and benomyl. Antagonistic tests showed that B. licheniformis J8 inhibited the phytopathogenic fungi Sclerotinia sclerotiorum and Sclerotium rolfsii, while qualitative mineral solubilization assays indicated the ability of selected isolates to mobilize phosphate and potassium. These findings highlight geothermal ecosystems as valuable reservoirs of thermotolerant bacteria with enzymatic versatility and environmental relevance, supporting further molecular and process-optimization studies.

Marine macroalgae (commonly known as seaweeds), a rich yet underexplored resource, have emerged as a promising source of bioactive compounds with potent antioxidant properties. While oxidative stress is a critical factor in the pathogenesis of numerous chronic diseases, including neurodegenerative disorders, cardiovascular conditions, and cancer, macroalgae-derived compounds such as polyphenols, carotenoids, peptides, and sulfated polysaccharides have demonstrated the ability to mitigate oxidative damage through multifaceted mechanisms. These compounds neutralize reactive oxygen species and modulate key cellular pathways involved in inflammation and apoptosis. Despite significant advancements, gaps persist in understanding the pharmacokinetics, bioavailability, and clinical applications of these bioactives. Additionally, the inefficiencies of traditional extraction methods call for adopting innovative, environmentally friendly techniques that preserve bioactivity. This review synthesizes current knowledge on the therapeutic potential of macroalgal bioactives, acknowledges the contributions of other marine algae where relevant, highlights challenges in their extraction, and proposes future directions for research and application.

The fruit of the Mexican madroño (Arbutus arizonica) has been consumed since pre-Columbian times by North American tribes and native groups in Mexico. Despite this, reports on its chemical composition and biological activity are limited. This work aims to determine the antioxidant, antiproliferative, and digestive enzyme inhibition activities of the methanol amberlite-retained extract of Mexican madroño. Results showed that madroño fruit is rich in antioxidants: DPPH (EC₅₀ = 0.89 ± 0.03 mg/mL), TEAC (1078 ± 4.9 μM/g), and hemolysis inhibition (IC₅₀ = 358.07 μg/mL), with high phenolic and flavonoid content at 15.92 ± 3.2 mg GAE/g and 4.33 ± 0.3 mg CA/g, respectively. Using analytical chromatography, gallic acid, vanillic acid, chlorogenic acid, ferulic acid, quercetin, and rutin were quantified. The extract also showed α-glucosidase inhibition (IC₅₀ = 3.1 ± 0.17 mg/mL), but no inhibition against α-amylase and lipase (>5 mg/mL), while showing antiproliferative activity against HeLa, HT-29, and MCF-7 cancer cell lines. These results point towards an interesting potential for the fruit of the A. arizonica as chemopreventive and hold potential for elaborating functional foods.

The production of second-generation bioethanol has several challenges, among them finding cheap and efficient enzymes for a sustainable process. In this work, we analyzed two native fungi, Cladosporium cladosporioides and Penicillium funiculosum, as a source of cellulolytic enzyme production, and corn stover, wheat bran, chickpeas, and bean straw as a carbon source in two fermentation systems: submerged and solid fermentation. Corn stover was selected for cellulase production in both fermentation systems, because we found the highest enzymatic activities when carboxymethyl cellulase activity (CMCase) was assessed using CMC as substrate. C. cladosporioides showed the highest CMCase activity (1.6 U/mL), while P. funiculosum had the highest filter paper activity (Fpase) (0.39 U/mL). The ß-glucosidase activities produced by both fungi were similar in submerged fermentation using corn stover as substrate. Through in-gel zymography, three polypeptides with cellulolytic activities were identified in each fungus: with molecular weights of ~ 38, 45 and 70 kDa in C. cladosporioides and ~ 21, 63 and 100 kDa in P. funiculosum. The best results for saccharification (10.11 g/L of reducing sugars) of diluted acid pretreated corn stover were obtained after 36 h of the hydrolytic process at pH 5 and 50 °C using the enzyme extract of P. funiculosum. This is the first report of cellulase identification in C. cladosporioides and the saccharification of corn stover using enzymes of this fungus. Enzymatic extracts of C. cladosporioides and P. funiculosum obtained from low-cost lignocellulosic biomass have great potential for use in the production of second-generation bioethanol.

Aspergillus nidulans produces several proteases. The prtA gene encodes a major protease, and two approaches were explored to achieve the overproduction of this enzyme. Molecular cloning of the mature form of this enzyme in Pichia pastoris resulted in the production of an inactive form. In addition, the presence of this enzyme was toxic for the host and resulted in cell lysis. The modification of the culture medium constituents resulted in a 6.4-fold increase in enzyme production. The main effect was achieved through the use of organic nitrogen sources. Although it was previously shown that the PrtA protease shows promiscuous esterase activity, the production of this enzyme was not induced by lipidic sources.

Cutinases are versatile carboxylic ester hydrolases with great potential in many biocatalytic processes, including biodiesel production. Genome sequence analysis of the model organism Aspergillus nidulans reveals four genes encoding putative cutinases. In this work, we purified and identified for the first time a cutinase (ANCUT2) produced by A. nidulans. ANCUT2 is a 29-kDa protein which consists of 255 amino acid residues. Comparison of the amino acid sequence of ANCUT2 with other microbial cutinase sequences revealed a high degree of homology with other fungal cutinases as well as new features, which include a serine-rich region and conserved cysteines. Cutinase production with different lipidic and carbon sources was also explored. Enzyme activity was induced by olive oil and some triacylglycerides and fatty acids, whereas it was repressed by glucose (1%) and other sugars. In some conditions, a 22-kDa post-translational processing product was also detected. The cutinase nature of the enzyme was confirmed after degradation of apple cutin.

Aspergillus nidulans PW1 produces an extracellular carboxylesterase activity that acts on several lipid esters when cultured in liquid media containing olive oil as a carbon source. The enzyme was purified by gel filtration and ion exchange chromatography. It has an apparent MW and pI of 37 kDa and 4.5, respectively. The enzyme efficiently hydrolyzed all assayed glycerides, but showed preference toward short- and medium-length chain fatty acid esters. Maximum activity was obtained at pH 8.5 at 40°C. The enzyme retained activity after incubation at pHs ranging from 8 to11 for 12 h at 37°C and 6 to 8 for 24 h at 37°C. It retained 80% of its activity after incubation at 30 to 70°C for 30 min and lost 50% of its activity after incubation for 15 min at 80°C. Noticeable activation of the enzyme is observed when Fe²⁺ ion is present at a concentration of 1 mM. Inhibition of the enzyme is observed in the presence of Cu²⁺, Fe³⁺, Hg²⁺, and Zn²⁺ ions. Even though the enzyme showed strong carboxylesterase activity, the deduced N-terminal amino acid sequence of the purified protein corresponded to the protease encoded by prtA gene.