Reutilization of waste fungal biomass for concomitant production of proteochitinolytic enzymes and their catalytic products by Alcaligenes faecalis SK10

Fungal biomass, being organic waste, could be an excellent source of protein, carbohydrate and minerals. However, it has not been exploited fully until now. Efficient management of this waste can not only address the environmental impact on its disposal but also yield value-added metabolites. In the present study, in order to explore its potential, we subjected dead fungal biomass of Aspergillus niger SKN1 as substrate for both fermentative and enzymatic biodegradation, respectively by potent proteo-chitinolytic bacteria Alcaligenes faecalis SK10 and its enzyme cocktail. The results revealed that reasonable amount of protease and chitinase could be biosynthesized by the fermentative mode of utilization, while a mixture of amino acid, peptides and low-molecular weight amino-sugar (mono and oligomeric form of N-acetylglucosamine) could be generated through enzymatic hydrolysis. The physicochemical condition of both the bioprocess was subsequently optimized through statistical approach. The projected utilization of waste zero-valued fungal biomass offer a sustainable and environmentally sound method for production of microbial metabolites and large scale execution of the same could be proficient and in tune with the principle of circular economy.

Immobilization of fungal biomass with multi-walled carbon nanotubes as biosorbent

@#Aim:This study was mainly highlighted on a combination of fungal biomass onto MWCNTs in order to enhance the positive integration of impurities removal in aqueous solution. Methodologyand results:The immobilization of fungal biomass and MWCNTs was done in a batch liquid medium with several factors such as agitation speed, dose of MWCNTs, pH and inoculum dosage that were conducted with one factor at one time (OFAT) method. Basically, to verify the functional group of MWCNTs, Aspergillusnigerbiomass and immobilized A. nigerbiomass, the FTIR was applied and FESEM was done to demonstrate andcompare the image of the immobilized A. nigerbiomass with MWCNTs and fungal biomass alone. The finding showed the best agitation speed, dose of MWCNTs, pH and inoculum dosage were 150 rpm, 0.5 g, 5-6 and 2% respectively. FTIR indicates the presents of the functional groups like –OH (3270 cm-1), C-O (1619 cm-1) and –CH (2915 cm-1) while FESEM illustrates the images of the wrapped MWCNTs on A. nigerbiomass. Conclusion, significance and impact of study:The conventional technique of adsorption of fungal biomass alone not showing a favorable removal of impurities. Thus, the immobilization of fungal biomass (A. niger) with multi-walled carbon nanotubes (MWCNTs) was a good combination since both have potential functional group to accumulate to each other and has a tendency to remove effectively and efficiently the impurities in aqueous solution.

Estimación de la biomasa fúngica en un suelo del sudoeste de la provincia de Buenos Aires (Argentina) con una tinción directa con blanco de calcoflúor / Fungal biomass estimation in soils from southwestern Buenos Aires province (Argentina) using calcofluor white stain

Los microorganismos del suelo son vitales para el correcto funcionamiento de los ecosistemas, principalmente por su papel en el ciclado de nutrientes. La intensificación del uso del suelo y las prácticas agrícolas alteran negativamente la actividad microbiana. La biomasa fúngica es uno de los parámetros más utilizados para estudiar el impacto de las actividades agrícolas en la estructura y el funcionamiento del suelo. El objetivo del presente trabajo fue estimar la biomasa fúngica en un suelo del sudoeste bonaerense con el fin de obtener valores de referencia que permitan usar este parámetro como un indicador de cambios en el ecosistema y, por otro lado, demostrar que la metodología empleada es sensible a las variaciones en las condiciones climáticas. Se colectaron muestras de suelos durante 2 años consecutivos. Se prepararon frotis de suelo y se tiñeron con soluciones de distintas concentraciones de blanco de calcoflúor y luego se estimó la biomasa fúngica observando los frotis con microscopio de epifluorescencia. Los valores de biomasa fúngica estimados variaron entre 2,23 y 26,89 μg Cfúngico/g de suelo y estuvieron dentro del rango esperable para el tipo de suelo estudiado. La biomasa fúngica mostró una relación positiva con la temperatura y las precipitaciones. La metodología empleada resultó ser confiable, repetible y sensible a cambios en las condiciones climáticas. Los resultados podrían usarse como valores de referencia para estudiar la biomasa fúngica de suelos bajo distintas condiciones y emplearse como indicadores del impacto de las distintas prácticas agrícolas sobre el ecosistema.

Soil microorganisms are vital for ecosystem functioning because of the role they play in soil nutrient cycling. Agricultural practices and the intensification of land use have a negative effect on microbial activities and fungal biomass has been widely used as an indicator of soil health. The aim of this study was to analyze fungal biomass in soils from southwestern Buenos Aires province using direct fluorescent staining and to contribute to its use as an indicator of environmental changes in the ecosystem as well as to define its sensitivity to weather conditions. Soil samples were collected during two consecutive years. Soil smears were prepared and stained with two different concentrations of calcofluor, and the fungal biomass was estimated under an epifluorescence microscope. Soil fungal biomass varied between 2.23 and 26.89 μg fungal C/g soil, being these values in the range expected for the studied soil type. The fungal biomass was positively related to temperature and precipitations. The methodology used was reliable, standardized and sensitive to weather conditions. The results of this study contribute information to evaluate fungal biomass in different soil types and support its use as an indicator of soil health for analyzing the impact of different agricultural practices.

The leaf breakdown of Picramnia sellowii (Picramniales: Picramniaceae) as index of anthropic disturbances in tropical streams / Decomposição de folhas de Picramnia sellowii (Picramniales: Picramniaceae) como índice de distúrbio antrópicos em riachos tropicais

Abstract There are few studies in tropical regions exploring the use of leaf breakdown process as a functional tool to assess anthropic disturbance on aquatic ecosystems. We assessed the effects of water pollution due to human activities on the leaf breakdown rate of Picramnia sellowii in streams of the southeastern Brazil. The experiment was carried out for 60 days in three reference streams and three streams impaired by organic pollution and absence of riparian vegetation. Three litter bags were incubated in each stream containing 3 ± 0.05 g of P. sellowii leaves. The reference streams presented higher values of dissolved oxygen and lower values of nutrients, turbidity, electrical conductivity, total impermeable area and water temperature. The leaf breakdown rate (k) differed significantly between the reference (k = 0.014 ± 0.003 d–1) and impaired streams (k = 0.005 ± 0.001 d–1). The leaves incubated in the reference streams contained greater fungal biomass (measured as ergosterol concentration) and abundance of invertebrates, as well as greater presence of shredders, with k values being related to the biomass of these organisms. Overall, there were clear differences between the leaf mass loss in the reference and impaired streams. These results reinforce the negative effect of urbanization on leaf breakdown and fungal and shredder biomass.

Resumo Na região tropical são escassos os estudos que exploram o uso do processo de decomposição foliar como ferramenta funcional para avaliar os efeitos das perturbações antrópicas sobre os ecossistemas aquáticos. Nosso objetivo foi avaliar os efeitos dos impactos antrópicos sobre a taxa de decomposição de Picramnia sellowii em riachos no Sudeste do Brasil. O experimento foi realizado durante 60 dias em três riachos referências e três impactados por poluição orgânica e sem cobertura vegetal. Em cada riacho foram incubados três sacos contendo 3 ± 0,05 g de folhas secas de P. sellowii. Os riachos referência apresentaram maiores concentrações de oxigênio dissolvido e menores valores de nutrientes, turbidez, condutividade elétrica, TIA (área total impermeável) e temperatura. O coeficiente de decomposição (k) diferiu entre os riachos referência (k = 0,014 ± 0,003 d–1) e os impactados (k = 0,005 ± 0,001 d–1). Nas folhas incubadas nos riachos referência foi observada maior biomassa de fungos e abundância de invertebrados, assim como a presença de fragmentadores, estando o k relacionado com a biomassa destes organismos. A decomposição se mostrou sensível para avaliar impactos antrópicos nos ecossistemas aquáticos uma vez que foram observadas nítidas diferenças entre a perda de massa foliar nos riachos referências e impactados. Estes resultados reforçam o efeito negativo da urbanização sobre a decomposição e biomassa de fungos e fragmentadores.

Inhibitory effect of various aqueous medicinal plant extracts on citrinin production and fungal biomass by Penicillium notatum and Aspergillus niger.

Citrinin is a nephrotoxic mycotoxin produced by several species of the genus Aspergillus, Penicillium and Monascus. Citrinin is generally formed after harvest and occurs mainly in stored grains The efficacy of different concentrations of aqueous leaf extracts of Aervalanata, Nerium oleander Rhazya stricta Decne and Cleome amblyocarpa (5 to 10 mg/mL) on growth and citrinin production in two fungal strains Penicillium notatum and Aspergillus niger was investigated. Mycotoxin production and fungal biomass by the isolates was suppressed, depending on the concentration of the plant extract added to culture media at the time of spore inoculation. Citrinin production in fungal mycelia grown for 15 days in culture media containing 5-10 mg/mL of the aqueous extracts of A. lanata, N. oleander, R. stricta Decne and C. amblyocarpa showed inhibition of approximately 14.2 to 91.8 % in Penicillium notatum and 13.4 to 90.3% in Aspergillus niger. Among the all four extracts Rhazya stricta Decne was more efficient than other tested plant extracts in inhibiting the citrinin production ranging from 22.4 to 91.8% in P. notatum and 32.6 to 93.2% in A. niger.

Biomasa fúngica y bacteriana como indicadoras del secuestro de C en suelos de sabanas sustituidos por pinares en Uverito, Venezuela

Fungal and bacterial biomass as indicators of soil C sequestration in savannas soils substituted by pine plantations. A transformation of any natural ecosystem to an agricultural or forest system leads to an important soil modification, not only in the total carbon pool, but also in the carbon associated to the microbial biomass. This way, carbon quantification on soil quality is important for the determination of impacts of agricultural practices and land use changes. The aim of this study was to the determine, through the selective inhibition technique, the fungal and bacterial biomass, and fungal-to-bacterial ratio (F:B) in pine plantations (Pinus caribaea var. hondurensis), to establish if these parameters are sensible indicators of changes in the carbon content in Uverito soils (Venezuela). Furthermore, the inhibitor additivity ratio (IAR) and total combined inhibition (TCI) were carried out to determine if the antibiotics caused non-target inhibition. The quantification of fungal and bacterial biomass was carried out by using of cyloheximide as fungal inhibitor, and streptomycin and chloranphenicol as specific bacterial inhibitors. This research evidences that this land use change exerted a significant effect on soil microbial biomass, and shows that in pine plantations there is a dominance of the fungal component, in contrast to the native savanna, in which the bacterial biomass dominates. The substitution of native savanna by pine plantation in Uverito promotes a major soil carbon sequestration. The values of the inhibitor additivity ratio (IAR) as for native savanna as pine system, were both>1.0. The total combined inhibition (TCI) was smaller in the pine systems, from which it is possible to infer that a high proportion of microbial biomass was affected by the combination of the inhibitors. Rev. Biol. Trop. 58 (3): 977-989. Epub 2010 September 01.

Cualquier transformación de un ecosistema natural a un sistema agrícola o forestal conduce a una modificación importante no sólo del pool del carbono total, sino también del carbono asociado con la biomasa microbiana. Su cuantificación es importante en la determinación del impacto de las prácticas agrícolas y el cambio de uso de la tierra sobre la calidad del suelo. El objetivo de este estudio fue determinar, a través del método de inhibición selectiva, la biomasa fúngica y bacteriana y la relación (H:B) en suelos de sabana nativa sustituidos por pinares (Pinus caribaea var. hondurensis), para establecer si éstos parámetros son indicadores sensibles de cambios en el contenido de carbono en suelos de Uverito, Venezuela. La relación de aditividad del inhibidor (RAI) y la inhibición total por efecto combinado del inhibidor (ITC) se llevaron a cabo para determinar, si los inhibidores microbianos tuvieron actividad sobre otros organismos para los cuales éstos no estaban destinados. La cuantificación de la biomasa fúngica y bacteriana se llevó a cabo mediante el uso de la cycloheximida como inhibidor fúngico, y la estreptomicina y el cloranfenicol como inhibidores bacterianos. Esta investigación evidencia que este cambio de uso de la tierra ejerció un efecto significativo sobre la biomasa microbiana del suelo, y muestra que en el sistema de pinares existe una dominancia del componente fúngico, en contraste con la sabana nativa, en la cual domina la biomasa bacteriana. La sustitución de la sabana nativa por plantaciones de pino en Uverito, promueve un mayor secuestro del carbono en el suelo. Los valores de la relación de aditividad del inhibidor (RAI) tanto para la sabana nativa como para el sistema de pinares, resultaron ambos >1.0. La inhibición total combinada (ITC) resultó menor en el sistema de pinares; a partir de lo cual, es posible inferir que una elevada proporción de la biomasa microbiana fue afectada por la combinación de los inhibidores.

Ergosterol and Water Changes in Tricholoma matsutake Soil Colony during the Mushroom Fruiting Season

The purpose of this study is to understand spatio-temporal changes of active fungal biomass and water in Tricholoma matsutake soil colonies during the mushroom fruiting season. The active fungal biomass was estimated by analyzing ergosterol content at four different points within four replicated locations in a single circular T. matsutake colony at Ssanggok valley in the Sogri Mt. National Park in Korea during 2003 to 2005. The four points were the ahead of the colony, the front edge of the colony and 20 cm and 40 cm back from the front edge of the colony. Ergosterol content was 0.0 to 0.7 microg per gram dried soil at the ahead, 2.5 to 4.8 microg at the front edge, 0.5 to 1.8 microg at the 20 cm back and 0.3 to 0.8 microg at the 40 cm back. The ergosterol content was very high at the front edge where the T. matsutake hyphae were most active. However, ergosterol content did not significantly change during the fruiting season, September to October. Soil water contents were lower at the front edge and 20 cm back from the front edge of the colony than at the ahead and 40 cm back during the fruiting season. Soil water content ranged from 12 to 19% at the ahead, 10 to 11% at the edge, 9 to 11% at the 20 cm back and 11 to 15% at the 40 cm back. Our results suggest that the active front edge of the T. matsutake soil colony could be managed in terms of water relation and T. matsutake ectomycorrhizal root development.

Production of tannase by Aspergillus tamarii in submerged cultures

The production of tannase by Aspergillus tamarii was studied in submerged cultures. The fungus produced an extracellular tannase after two days of growth in mineral medium containing tannic acid, gallic acid and methyl gallate as carbon source. The best result was obtained using gallic acid as inducer (20.6 U/ml). The production of enzyme was strongly repressed by the presence of glucose. Crude enzyme was optimally active at pH 5.0 and 30º C. The enzyme was stable in a large range of pH and up to the temperature of 45º C.

A produção de tanase por um novo potencial produtor, o fungo filamentoso Aspergillus tamarii, foi parcialmente caracterizada neste estudo. O fungo produziu uma tanase extracelular em culturas submersas após 2 dias de crescimento em meio mineral contendo ácido tânico, ácido gálico ou metil galato como fonts de carbono. Os melhores resultados foram obtidos em culturas com ácido gálico (20,6 U/ml). A produção da enzima foi fortemente inibida por glicose. A enzima bruta foi otimamente ativa em pH 5,0 e a 30º C e estável em ampla faixa de pH e em temperaturas inferiores a 45ºC.