Penicillium and Talaromyces endophytes from Tillandsia catimbauensis, a bromeliad endemic in the Brazilian tropical dry forest, and their potential for L-asparaginase production

Evaluation of the efficiency of thermostable L-asparaginase from B. licheniformis UDS-5 for acrylamide mitigation during preparation of French fries

A thermostable L-asparaginase was produced from Bacillus licheniformis UDS-5 (GenBank accession number, OP117154). The production conditions were optimized by the Plackett Burman method, followed by the Box Behnken method, where the enzyme production was enhanced up to fourfold. It secreted L-asparaginase optimally in the medium, pH 7, containing 0.5% (w/v) peptone, 1% (w/v) sodium chloride, 0.15% (w/v) beef extract, 0.15% (w/v) yeast extract, 3% (w/v) L-asparagine at 50 °C for 96 h. The enzyme, with a molecular weight of 85 kDa, was purified by ion exchange chromatography and size exclusion chromatography with better purification fold and percent yield. It displayed optimal catalysis at 70 °C in 20 mM Tris-Cl buffer, pH 8. The purified enzyme also exhibited significant salt tolerance too, making it a suitable candidate for the food application. The L-asparaginase was employed at different doses to evaluate its ability to mitigate acrylamide, while preparing French fries without any prior treatment. The salient attributes of B. licheniformis UDS-5 L-asparaginase, such as greater thermal stability, salt stability and acrylamide reduction in starchy foods, highlights its possible application in the food industry.

In Vitro Assessment of Eight Selected Indigenous Fungal Isolates Tolerance to Various Abiotic Stresses and their Effects on Seed Germination

Fungal bio-control agents (BCA) can minimize use of agro-chemicals while increasing plant productivity and tolerance to biotic-abiotic stressors. Ideally, BCA should tolerate varying environmental conditions they are introduced into, to successfully dominate and protect plants from stressors. However, BCA are living micro-organisms, their survival and efficacy can be impeded by extreme conditions. The current study aimed at evaluating whether indigenous fungal isolates, viz, Aspergillus flavus, A. terreus, Penicillium sp. AL-38 IRH-2012b, Talaromyces minioluteus, T. purpureogenus, T. sayulitensis, Trichoderma ghanense and T. viride can tolerate different levels of salinity, pH, nutrient and temperature. Certain fungal species are pests with potential of destroying many crops; the pathogenic effects of the aforementioned fungal isolates were further assessed on different crops' seeds. The results showed that, although being indigenous, Aspergillus, T. sayulitensis and T. ghanense failed to thrive in high salinity and pH. While Penicillium sp. AL-38 IRH-2012b failed to thrive under reduced nutrient level and all fungal isolates failed to grow at 10-20 °C. Furthermore, it was noted species within the same genus could affect crops in both favorable and unfavorable ways. The study demonstrated that the selected indigenous fungal isolates can tolerate different abiotic conditions and have potential to improve seed germination and seedling growth.

Endophytic Fungi as a Promising Source of Anticancer L-Asparaginase: A Review

L-asparaginase is a tetrameric enzyme from the amidohydrolases family, that catalyzes the breakdown of L-asparagine into L-aspartic acid and ammonia. Since its discovery as an anticancer drug, it is used as one of the prime chemotherapeutic agents to treat acute lymphoblastic leukemia. Apart from its use in the biopharmaceutical industry, it is also used to reduce the formation of a carcinogenic substance called acrylamide in fried, baked, and roasted foods. L-asparaginase is derived from many organisms including plants, bacteria, fungi, and actinomycetes. Currently, L-asparaginase preparations from Escherichia coli and Erwinia chrysanthemi are used in the clinical treatment of acute lymphoblastic leukemia. However, they are associated with low yield and immunogenicity problems. At this juncture, endophytic fungi from medicinal plants have gained much attention as they have several advantages over the available bacterial preparations. Many medicinal plants have been screened for L-asparaginase producing endophytic fungi and several studies have reported potent L-asparaginase producing strains. This review provides insights into fungal endophytes from medicinal plants and their significance as probable alternatives for bacterial L-asparaginase.

Anticancer Asparaginases: Perspectives in Using Filamentous Fungi as Cell Factories

The enzyme L-asparaginase (L-asparagine amidohydrolase) catalyzes the breakdown of L-asparagine into aspartate and ammonia, which leads to an anti-neoplastic activity stemming from its capacity to deplete L-asparagine concentrations in the bloodstream, and it is therefore used in cases of acute lymphoblastic leukemia (ALL) to inhibit malignant cell growth. Nowadays, this anti-cancer enzyme, largely produced by Escherichia coli, is well established on the market. However, E. coli L-asparaginase therapy has side effects such as anaphylaxis, coagulation abnormality, low plasma half-life, hepatotoxicity, pancreatitis, protease action, hyperglycemia, and cerebral dysfunction. This review provides a perspective on the use of filamentous fungi as alternative cell factories for L-asparaginase production. Filamentous fungi, such as various Aspergillus species, have superior protein secretion capacity compared to yeast and bacteria and studies show their potential for the future production of proteins with humanized N-linked glycans. This article explores the past and present applications of this important enzyme and discusses the prospects for using filamentous fungi to produce safe eukaryotic asparaginases with high production yields.

Fungal endophytes from leaves of Mandevilla catimbauensis (Apocynaceae): diversity and potential for L-asparaginase production

In this study, we examined endophytic fungi in leaves of Mandevilla catimbauensis, an endemic plant species found in the Brazilian dry forest (Caatinga), and endophytic fungi's potential to produce L-asparaginase (L-ASNase). In total, 66 endophytes were isolated, and the leaf-fragment colonisation rate was 11.78%. Based on morphology, internal transcribed spacer (ITS), and partial large subunit (LSU) of ribosomal DNA sequencing, the endophytic fungi isolated belonged to six Ascomycota orders (Botryosphaeriales, Capnodiales, Diaporthales, Eurotiales, Marthamycetales, and Pleosporales). Phyllosticta species were the most frequent endophytes isolated (23 isolates [45.1%] from two species). The Shannon-Wiener and Fisher alpha index average values were 0.56 and 3.26, respectively. Twenty endophytes were randomly selected for the L-ASNase production test, of which fourteen isolates showed potential to produce the enzyme (0.48-2.22 U g-1), especially Phyllosticta catimbauensis URM 7672 (2.22 U g-1) and Cladosporium sp. G45 (2.11 U g-1). Phyllosticta catimbauensis URM 7672 was selected for the partial optimisation of L-ASNase production because of its ability to generate considerable amounts of enzyme. We obtained the highest L-ASNase activity (3.47 U g-1), representing an increase of 36.02% in enzymatic production, under the following experimental conditions: a pH of 4.2, 1.0% inoculum concentration, and 2.5% L-asparagine concentration. Our study showed that M. catimbauensis harbours an important diversity of endophytic fungi with biotechnological potential for L-ASNase production.

Magalhães P. Filamentous Fungi Producing l-Asparaginase with Low Glutaminase Activity Isolated from Brazilian Savanna Soil

l-asparaginase is an enzyme used as treatment for acute lymphoblastic leukemia (ALL) due to its ability to hydrolyze l-asparagine, an essential amino acid synthesized by normal cells unlike neoplastic cells. The adverse effects of l-asparaginase formulations are associated with its glutaminase activity and bacterial origin; therefore, it is important to find new sources of l-asparaginase-producing eukaryotic microorganisms with low glutaminase activity. This work evaluated the biotechnological potential of filamentous fungi isolated from Brazilian Savanna soil and plants for l-asparaginase production. Thirty-nine isolates were screened for enzyme production using the plate assay, followed by measuring enzymatic activity in cells after submerged fermentation. The variables influencing l-asparaginase production were evaluated using Plackett-Burman design. Cell disruption methods were evaluated for l-asparaginase release. Penicillium sizovae 2DSST1 and Fusarium proliferatum DCFS10 showed the highest l-asparaginase activity levels and the lowest glutaminase activity levels. Penicillium sizovae l-asparaginase was repressed by carbon sources, whereas higher carbon concentrations enhanced l-asparaginase by F. proliferatum. Maximum enzyme productivity, specific enzyme yield and the biomass conversion factor in the enzyme increased after Plackett-Burman design. Freeze-grinding released 5-fold more l-asparaginase from cells than sonication. This study shows two species, which have not yet been reported, as sources of l-asparaginase with possible reduced immunogenicity for ALL therapy.

Endophytic Penicillium species and their agricultural, biotechnological, and pharmaceutical applications

Penicillium genus constituted by over 200 species is one of the largest and fascinating groups of fungi, particularly well established as a source of antibiotics. Endophytic Penicillium has been reported to colonize their ecological niches and protect their host plant against multiples stresses by exhibiting diverse biological functions that can be exploited for countless applications including agricultural, biotechnological, and pharmaceutical. Over the past 2 decades, endophytic Penicillium species have been investigated beyond their antibiotic potential and numerous applications have been reported. We comprehensively summarized in this review available data (2000-2019) regarding bioactive compounds isolated from endophytic Penicillium species as well as the application of these fungi in multiple agricultural and biotechnological processes. This review has shown that a very large number (131) of endophytes from this genus have been investigated so far and more than 280 compounds exhibiting antimicrobial, anticancer, antiviral, antioxidants, anti-inflammatory, antiparasitics, immunosuppressants, antidiabetic, anti-obesity, antifibrotic, neuroprotective effects, and insecticidal and biocontrol activities have been reported. Moreover, several endophytic Penicillium spp. have been characterized as biocatalysts, plant growth promoters, phytoremediators, and enzyme producers. We hope that this review summarizes the status of research on this genus and will stimulate further investigations.