Exploring the biosorption of nickel and lead by Fusarium sp. biomass: kinetic, isotherm, and thermodynamic assessment.

Fungal biomass is as a cost-effective and sustainable biosorbent utilized in both active and inactive forms. This study investigated the efficacy of inactivated and dried biomass of Fusarium sp. in adsorbing Ni2+ and Pb2+ from aqueous solutions. The strain underwent sequential cultivation and was recovered by filtration. Then, the biomass was dried in an oven at 80 ± 2 °C and sieved using a 0.1-cm mesh. The biosorbent was thoroughly characterized, including BET surface area analysis, morphology examination (SEM), chemical composition (XRF and FT-IR), thermal behavior (TGA), and surface charge determination (pH-PZC and zeta potential). The biosorption mechanism was elucidated by fitting equilibrium models of kinetics, isotherm, and thermodynamic to the data. The biosorbent exhibited a neutral charge, a rough surface, a relatively modest surface area, appropriate functional groups for adsorption, and thermal stability above 200 °C. Optimal biosorption was achieved at 25 ± 2 °C, using 0.05 g of adsorbent per 50 mL of metallic ion solution at initial concentrations ranging from 0.5 to 2.0 mg L-1 and at pH 4.5 for Pb2+ and Ni2+. Biosorption equilibrium was achieved after 240 min for Ni2+ and 1440 min for Pb2+. The process was spontaneous, mainly through chemisorption, in monolayer for Ni2+ and multilayer for Pb2+, with efficiencies of over 85% for both metallic ion removal. These findings underscore the potential of inactive and dry Fusarium sp. biomass (IDFB) as a promising material for the biosorption of Ni2+ and Pb2+.

Improvement Production of Hyaluronic Acid by Streptococcus zooepidemicus in Sugarcane Molasses.

Microbial hyaluronic acid (HA) production has been preferred rather than extraction from animal tissue for medical and cosmetic applications. In this context, to obtain an economically competitive HA production by Streptococcus zooepidemicus, culture conditions were studied to improve the polymer production in sugarcane molasses. The highest HA production by S. zooepidemicus ATCC 39920 achieved was 2.825 g. L-1 in a 4.5 L bioreactor with controlled pH (8.0) and medium containing molasses (85.35 g.L-1 total sugar) pretreated with activated charcoal and yeast extract (50 g.L-1). The HA produced exhibited a high molecular weight of 1.35 × 103 kDa and the DPPH radical scavenging activity of the polymer at 1 g.L-1 was 41 %. The FTIR and UV-Vis spectra showed no substantial differences in the spectral pattern between produced and standard HA. This study is a promising strategy for sugarcane molasses application by producing high value-added products such as hyaluronic acid.

ß-(1→3,1→6)-d-glucans produced by Diaporthe sp. endophytes: Purification, chemical characterization and antiproliferative activity against MCF-7 and HepG2-C3A cells.

This study reports the characterization and antiproliferative activity of exopolysaccharides (EPS) produced by submerged cultures of the endophytes Diaporthe sp. JF766998 and Diaporthe sp. JF767007 isolated from the medicinal plant Piper hispidum Sw. Both strains secreted a crude EPS that, upon size exclusion chromatography, showed to contain a heteropolysaccharide (galactose, glucose and mannose) and a high-molecular weight glucan. Data from methylation analysis, FTIR and NMR spectroscopy (1H, COSY, TOCSY and HSQC-DEPT) indicated that the purified glucan consisted of a main chain of glucopyranosyl ß-(1→3) linkages substituted at O-6 by glucosyl residues. According to MTT assay, some treatments of both ß-glucans have antiproliferative activity against human breast carcinoma (MCF-7) and hepatocellular carcinoma (HepG2-C3A) cells after 24 and 48h of treatment, exhibiting a degree of inhibition ratio that reached the highest values at 400µg/mL: 58.0% (24h) and 74.6% (48h) for MCF-7 cells, and 61.0% (24h) and 83.3% (48h) for HepG2-C3A cells. These results represent the first reports on the characterization and antiproliferative effect of ß-glucans from Diaporthe species and also expand the knowledge about bioactive polysaccharides from endophytic sources.

Screening of endophytic sources of exopolysaccharides: Preliminary characterization of crude exopolysaccharide produced by submerged culture of Diaporthe sp. JF766998 under different cultivation time.

Endophytic fungi have been described as producers of important bioactive compounds; however, they remain under-exploited as exopolysaccharides (EPS) sources. Therefore, this work reports on EPS production by submerged cultures of eight endophytes isolated from Piper hispidum Sw., belonging to genera Diaporthe, Marasmius, Phlebia, Phoma, Phyllosticta and Schizophyllum. After fermentation for 96 h, four endophytes secreted EPS: Diaporthe sp. JF767000, Diaporthe sp. JF766998, Diaporthe sp. JF767007 and Phoma herbarumJF766995. The EPS from Diaporthe sp. JF766998 differed statistically from the others, with a higher percentage of carbohydrate (91%) and lower amount of protein (8%). Subsequently, this fungus was grown under submerged culture for 72, 96 and 168 h (these EPS were designated EPSD1-72, EPSD1-96 and EPSD1-168) and the differences in production, monosaccharide composition and apparent molecular were compared. The EPS yields in mg/100 mL of culture medium were: 3.0 ± 0.4 (EPSD1-72), 15.4 ± 2.2 (EPSD1-96) and 14.8 ± 1.8 (EPSD1-168). The EPSD1-72 had high protein content (28.5%) and only 71% of carbohydrate; while EPSD1-96 and EPSD1-168 were composed mainly of carbohydrate (≈95 and 100%, respectively), with low protein content (≈5%) detected at 96 h. Galactose was the main monosaccharide component (30%) of EPSD1-168. Differently, EPSD1-96 was rich in glucose (51%), with molecular weight of 46.6 kDa. It is an important feature for future investigations, because glucan-rich EPS are reported as effective antitumor agents.

Toxicity of ß-(1→3, 1→6)-á´ -glucans produced by Diaporthe sp. endophytes on Metarhizium anisopliae (Metschnikoff) Sorokin assessed by conidia germination speed parameter / Toxicidade de ß- (1 → 3, 1 → 6) -á´ -glucanas produzidas por endófitos Diaporthe sp. sobre Metarhizium anisopliae (Metschnikoff) Sorokin avaliada pelo parâmetro de velocidade de germinação dos conídios

We have previously reported that ß-(1→3,1→6)-ᴅ-glucans produced by endophytes Diaporthe sp. G27-60 and G65-65 (GenBank accession codes JF766998 and JF767007, respectively) are promising anti-proliferation agents against human breast carcinoma (MCF-7) and hepatocellular carcinoma (HepG2-C3A) cells. However, the literature fails to describe the effects of Diaporthe exopolysaccharides (EPS) on eukaryotic healthy cells. The fungus Metarhiziumanisopliae has been employed as model-system to evaluate the toxicity of pharmaceutical and agricultural-interest substances, taking into account, among other parameters, the speed of conidia germination. Current study verified the effect of different concentrations of Diaporthe ß-glucans on the germination speed of M. anisopliae. Conidia were incubated with ß-glucans treatments (50, 200 and 400 µg/mL) at 28ºC, sampled during 24 h and analyzed by light microscopy. At the end of a 24-h incubation, the amount of germinated conidia reached ≈99% for controls and ranged between 97.7 and 98.6% for treatments. Bayesian analysis indicated that Diaporthe glucans had no toxicity on M. anisopliaeand the curve of germination occurred as expected for this fungal strain. Considering the validity of filamentous fungi as model-systems, results are important data on the toxicity of endophytic EPS on healthy cells and may be associated with our previous results obtained for these polymers against tumor cells.

Anteriormente, um estudo mostrou que ß-(1→3,1→6)-ᴅ-glucanas produzidas pelos endófitos Diaporthe sp. G27-60 e G65-65 (códigos de acesso no GenBank JF766998 e JF767007, respectivamente) são agentes promissores com ação antiproliferativa contra células HepG2-C3A (hepatoma humano) e MCF-7 (adenocarcinoma mamário humano). No entanto, os efeitos de exopolissacarídeos (EPS) produzidos por fungos do gênero Diaporthe em células eucarióticas sadias não estão descritos na literatura atual. O fungo Metarhiziumanisopliae tem sido utilizado como sistema-modelo para avaliar a toxicidade de substâncias de interesse farmacêutico e agronômico, considerando, entre outros parâmetros, a velocidade de germinação de conídios. O presente estudo teve como objetivo verificar os efeitos de diferentes concentrações de ß-glucanas produzidas por Diaporthe sp. sobre a velocidade de germinação de M. anisopliae. Os conídios foram incubados com os tratamentos de ß-glucanas (50, 200 e 400 µg/mL) a 28 ºC, com amostras coletadas ao longo de 24 h, e analisados por microscopia de luz. Ao final das 24 h de incubação, o total de conídios germinados nos controles foi de ≈99%, e variou entre 97,7 e 98,6% para os tratamentos. A análise bayesiana indicou que as glucanas de Diaporthe sp. não apresentaram toxicidade sobre M. anisopliae, e a curva de germinação atendeu ao esperado para essa linhagem fúngica. Considerando a validade dos fungos filamentosos como sistemas-modelo, esses resultados representam dados importantes sobre a toxicidade dos EPS de endófitos sobre células sadias e podem ser associados aos resultados anteriormente obtidos para esses polímeros em testes contra células tumorais.

Xylanase production by Trichoderma harzianum rifai by solid state fermentation on sugarcane bagasse

Sugarcane bagasse was used as substrate for xylanase production by means of a strain of Trichoderma harzianum Rifai isolated from decaying Aspidosperma sp. (peroba) wood. The bagasse was washed, dried, milled and wetted with minimal salts medium and the cultures grown at 28 ñ 2§C for 7 days. Two extraction methods were tested for enzyme recovery: (A) Tween 80, 0.1(per cent) (v/v), in physiological saline, and (B) 50mM sodium acetate buffer, pH 5.0, under agitation (180rpm) for 15, 30 and 60min. After a single extraction, both extraction methods recovered an average of 15U/ml of xylanase activity, independent on the time of shaking. A second and third extraction recovered 10.4 and 6.6U/ml xylanase, respectively. The effect of volume size for extraction, and sugarcane bagasse concentration, on xylanase production were also investigated. The growth profile of Trichoderma harzianum was followed over 20 days on 14(per cent) (w/v) bagasse, and highest xylanase activity (288U/ml) appeared on the seventh day. The enzymatic extract after precipitation with ammonium sulphate was submitted to electrophoresis on polyacrylamide gels and showed 4 protein-staining bands, one of which exhibited xylanase activity.