José Maria Rodrigues da Luz

Enrichment of mushrooms: An interesting strategy for the acquisition of lithium

The capability of Pleurotus ostreatus mushroom to accumulate lithium (Li) and the accessibility of this Li compared with lithium carbonate (Li(2)CO(3)), often used as psychiatric medicine, were investigated. Mushrooms were produced on a substrate-based on coffee husk, with different added concentrations of lithium chloride (LiCl). Biological efficiency (BE), the crude protein content, the concentration of Li and other elements present in mushrooms were determined. The sequential extraction and in vitro test were used to verify the accessibility and the degree of solubility of this element. Li concentration in mushrooms was directly influenced by increasing LiCl concentration in the substrate (P<0.05). The BE was not affected by different concentrations of LiCl. Li present in enriched mushrooms showed greater accessibility than in Li(2)CO(3). Therefore, P. ostreatus mushrooms, enriched with lithium can be an alternative source of Li, as well as being a food with high nutritional value.

Degradation of Oxo-Biodegradable Plastic by Pleurotus ostreatus

Growing concerns regarding the impact of the accumulation of plastic waste over several decades on the environmental have led to the development of biodegradable plastic. These plastics can be degraded by microorganisms and absorbed by the environment and are therefore gaining public support as a possible alternative to petroleum-derived plastics. Among the developed biodegradable plastics, oxo-biodegradable polymers have been used to produce plastic bags. Exposure of this waste plastic to ultraviolet light (UV) or heat can lead to breakage of the polymer chains in the plastic, and the resulting compounds are easily degraded by microorganisms. However, few studies have characterized the microbial degradation of oxo-biodegradable plastics. In this study, we tested the capability of Pleurotus ostreatus to degrade oxo-biodegradable (D2W) plastic without prior physical treatment, such as exposure to UV or thermal heating. After 45 d of incubation in substrate-containing plastic bags, the oxo-biodegradable plastic, which is commonly used in supermarkets, developed cracks and small holes in the plastic surface as a result of the formation of hydroxyl groups and carbon-oxygen bonds. These alterations may be due to laccase activity. Furthermore, we observed the degradation of the dye found in these bags as well as mushroom formation. Thus, P. ostreatus degrades oxo-biodegradable plastics and produces mushrooms using this plastic as substrate.

Bio-Detoxification of Jatropha Seed Cake and Its Use in Animal Feed

Biodiesel production using the seed oil of Jatropha curcas L. (physic nut), as a raw material, results in large amounts of solid residue, called Jatropha seed cake. This seed cake contains lignocellulosic compounds, water, minerals and proteins [1-3]. However, it also contains toxic compounds and anti-nutritional factors [1-3]. The detoxification and reuse of this seed cake is very important for adding economic value, and also reduces potential environmental damage caused by improper disposal of this by-product.

Selenium Bioaccumulation in Shiitake Mushrooms: A Nutritional Alternative Source of this Element

UNLABELLED Mushrooms have effective mechanisms to absorb and accumulate trace elements from substrates and, therefore could be used as a strategy to produce mineral-enriched food and nutritional supplements. This study aimed to enrich shiitake mushrooms with selenium (Se), an important dietary element in human health. Strains of Lentinula edodes (Berk.) were grown on artificial logs composed of eucalyptus sawdust, and were subjected to cold shock in water containing sodium selenite (Na(2)SeO(3) ) at concentrations of up to 1.28 mM. The content of Se in the mushrooms increased linearly with increasing amounts of Na(2)SeO(3) added to the cold water although above 0.96 mM, mushroom formation was inhibited. Concentrations greater than 17 mg Se 100/g of dried mushrooms were observed after treatment with 0.64 mM Na(2)SeO(3). Shiitake mushroom had a demonstrate potential to offer an effective and economical way to produce Se-enriched products and, the strategy of adding selenite in cold water, used in this study, showed promising once it does not interfere with mycelial growth. PRACTICAL APPLICATION Selenium is an essential trace element for both human and animals and is required for the 21st amino acid, selenocysteine, which is used for the synthesis of about a dozen selenoenzymes. In this study, it is demonstrated that shiitake mushroom is a good Se accumulator and only one step during fructification was necessary to obtained enriched mushroom. Se enriched shiitake mushroom can be considered to be an excellent source of this element and used to consumption in different ways.

Colonização micorrízica em plantios de eucalipto

A associacao micorrizica e advinda da associacao simbiotica entre alguns fungos do solos e da maioria das raizes das plantas. O eucalipto possui a capacidade de se associar com dois tipos de micorrizas, a micorriza arbuscular e a ectomicorriza, o que depende muito da sua idade. Este trabalho objetivou avaliar a taxa de colonizacao por fungos micorrizicos arbusculares (MA) e ectomicorrizicos (ECM) e o numero de esporos de fungos micorrizicos arbusculares em plantios comerciais de Eucalyptus grandis e Eucalyptus urophylla, com diferentes idades e manejos, no periodo de dezembro de 2002 a fevereiro de 2004, na regiao leste de Minas Gerais, Brasil. Em todas as coletas e em todas as idades dos plantios, foram encontradas MA, e ECM e a media geral da colonizacao por fungos micorrizicos arbusculares (FMA) foi de 26%. O numero medio de esporos desses fungos de 374,7 por 100 g de solo e a colonizacao por fungos ectomicorrizicos (FECM) de 20,2%. As maiores porcentagens de colonizacao por FECM foram observadas em areas de plantios mais jovens, mas a sua maior diversidade foi observada nas areas de plantios mais velhos. Conclui-se que a epoca de coleta, a idade do plantio e o manejo do solo afetam a colonizacao micorrizica e tambem a diversidade de fungos ECM e que a sucessao de eucalipto com FMA-FECM nao e regra e e muito influenciada pelo tipo de manejo.

Enzymatic extract containing lignin peroxidase immobilized on carbon nanotubes: Potential biocatalyst in dye decolourization

The majority of the textile dyes are harmful to the environment and potentially carcinogenic. Among strategies for their exclusion, the treatment of dye contaminated wastewater with fungal extract, containing lignin peroxidase (LiP), may be useful. Two fungi isolates, Pleurotus ostreatus (PLO9) and Ganoderma lucidum (GRM117), produced the enzymatic extract by fermentation in the lignocellulosic residue, Jatropha curcas seed cake. The extracts from PLO9 and GRM117 were immobilized on carbon nanotubes and showed an increase of 18 and 27-fold of LiP specific activity compared to the free enzyme. Also, LiP from both fungi extracts showed higher Vmax and lower Km values. Only the immobilized extracts could be efficiently reused in the dye decolourization, contrary, the carbon nanotubes became saturated and they should be discarded over time. This device may offer a final biocatalyst with higher catalytic efficiency and capability to be reused in the dye decolourization process.

Abiotic and biotic degradation of oxo-biodegradable plastic bags by Pleurotus ostreatus.

In this study, we evaluated the growth of Pleurotus ostreatus PLO6 using oxo-biodegradable plastics as a carbon and energy source. Oxo-biodegradable polymers contain pro-oxidants that accelerate their physical and biological degradation. These polymers were developed to decrease the accumulation of plastic waste in landfills. To study the degradation of the plastic polymers, oxo-biodegradable plastic bags were exposed to sunlight for up to 120 days, and fragments of these bags were used as substrates for P. ostreatus. We observed that physical treatment alone was not sufficient to initiate degradation. Instead, mechanical modifications and reduced titanium oxide (TiO2) concentrations caused by sunlight exposure triggered microbial degradation. The low specificity of lignocellulolytic enzymes and presence of endomycotic nitrogen-fixing microorganisms were also contributing factors in this process.

Degradation of Green Polyethylene by Pleurotus ostreatus.

We studied the biodegradation of green polyethylene (GP) by Pleurotus ostreatus. The GP was developed from renewable raw materials to help to reduce the emissions of greenhouse gases. However, little information regarding the biodegradation of GP discarded in the environment is available. P. ostreatus is a lignocellulolytic fungus that has been used in bioremediation processes for agroindustrial residues, pollutants, and recalcitrant compounds. Recently, we showed the potential of this fungus to degrade oxo-biodegradable polyethylene. GP plastic bags were exposed to sunlight for up to 120 days to induce the initial photodegradation of the polymers. After this period, no cracks, pits, or new functional groups in the structure of GP were observed. Fragments of these bags were used as the substrate for the growth of P. ostreatus. After 30 d of incubation, physical and chemical alterations in the structure of GP were observed. We conclude that the exposure of GP to sunlight and its subsequent incubation in the presence of P. ostreatus can decrease the half-life of GP and facilitate the mineralization of these polymers.

Production of Selenium-Enriched Mushrooms in Coffee Husks and Use of This Colonized Residue

The sustainability of the coffee production chain involves the recovery of its byproducts. The coffee husk represents approximately 40% of the fruit. A small portion of this byproduct is used as organic fertilizer, while most of the coffee husk is discarded in the environment or incinerated. The use of waste such as the coffee husk for food production is limited due to the presence of antinutritional components (tannins and caffeine) and high-fiber content. The production of edible mushrooms using coffee husks is an option for recovering this byproduct because of the fungis ability to degrade these compounds and convert the lignocellulosic residues to food with high commercial and nutritional value. Moreover, with the use of these fungi, this byproduct can also be used to enrich mushrooms with selenium or other minerals important for human health and to produce lignocellulolytic enzymes or animal feed.