Production of polygalacturonases by Aspergillus section Nigri strains in a fixed bed reactor

Biochemical Prospects of Various Microbial Pectinase and Pectin: An Approachable Concept in Pharmaceutical Bioprocessing

Both pectin and pectinase are vitally imperative biomolecules in the biotechnological sector. These molecules are a feasible non-toxic contrivance of nature with extensive applicative perception. Understanding pectic substances and their structure, unique depolymerization, and biochemical properties such as a catalytic mechanism and the strong interrelationship among these molecules could immensely enhance their applicability in industries. For instance, gaining knowledge with respect to the versatile molecular heterogeneity of the compounds could be considered as the center of concern to resolve the industrial issues from multiple aspects. In the present review, an effort has been made to orchestrate the fundamental information related to structure, depolymerization characteristics, and classification of pectin as well as the types and biochemical properties of pectinase. Furthermore, various production methods related to the optimization of the product and its significant contribution to the pharmaceutical industry (either pectinase or derived pectic substances) are described in this article.

Polyphasic, Including MALDI-TOF MS, Evaluation of Freeze-Drying Long-Term Preservation on Aspergillus (Section Nigri) Strains

This study aims to evaluate the effect of freeze-drying and long-term storage on the biotechnological potential of Aspergillus section Nigri strains. Twelve selected strains were freeze-dried and aged by accelerated storage, at 37 °C in the dark, for 2 and 4 weeks. To assess possible changes as a consequence of the ageing in the freeze-drying ampoules, morphological characteristics, mycotoxins and enzymes production, matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALTI-TOF MS) spectra, and M13 phage probe fingerprinting were used as part of a polyphasic approach. Phenotypical changes were observed; nevertheless, they did not substantially affect the potential biotechnological use of these strains. The activity of hydrolytic enzymes (protease, carboxymethylcellulase, xylanase, pectinase and mannanase) was maintained or increased after freeze-drying. MALDI-TOF MS data originated spectra that grouped, for the majority of samples, according to strain independently of preservation time point. M13 profiles revealed the presence of some genetic polymorphisms after preservation. However, the three studied times still clustered for more than 50% of strains. Our results show that the studied strains maintain their biotechnological potential after preservation, with minimal phenotypic alterations. These findings provide evidence that freeze-drying preservation is a suitable option to preserve biotechnologically relevant aspergilli strains from section Nigri, and one should consider that the observed effects might be species/strain-dependent.

Bioreactors in solid state fermentation technology: Design, applications and engineering aspects

In recent years, substantial credibility in employing Solid-State Fermentation (SSF) technique has been witnessed owing to its numerous advantages over submerged fermentation (SmF). In spite of enormous advantages, true potential of SSF technology has not been fully realized at industrial scale. The lack of rational and scalable bioreactor designs backed by mathematical models and automated control system that could successfully address heterogeneity with respect to heat and mass, and also operate aseptically, remains the prime reason for it. As a result, there still exists vast scope in SSF bioreactor research and development to facilitate broad spectrum of biotechnological applications. The present article reviews state-of-the-art in SSF technology with focus on bioreactors that have been employed for bioprocess applications, in particular, enzyme production. Based on the mode of operation, bioreactors are divided into four categories with emphasis on design features, effect of operating conditions on productivity, applications and limitations. Selected modeling studies developed over the years, have been revised and presented in problem specific manner in order to address the limitations. Some interesting designs including few recent ones that have been proposed and/or employed at pilot and industrial levels are discussed in more detail.

Comparison between several reactors with Trametes versicolor immobilized on lignocellulosic support for the continuous treatments of hospital wastewater

Hospital wastewater is a major source of pharmaceutically active compounds (PhACs), which are not all removed in conventional wastewater treatment plants. White rot fungi can degrade PhACs, but their application has been limited to non-sterile conditions due to the competition with other microorganisms for growth. In this study, immobilization of Trametes versicolor on different lignocellulosic supports was studied as strategy to ensure fungal survival under continuous treatment conditions. A fluidized bed reactor and a trickling packed-bed reactor with T. versicolor immobilized on pallet wood were employed for the removal of ibuprofen, ketoprofen and naproxen. Best results were obtained with the trickling packed-bed reactor, which operated for 49days with high removal values in real hospital wastewater.

Requalification of a Brazilian Trichoderma Collection and Screening of Its Capability to Decolourise Real Textile Effluent

Water contamination with large amounts of industrial textile coloured effluents is an environmental concern. For the treatment of textile effluents, white-rot fungi have received extensive attention due to their powerful capability to produce oxidative (e.g., ligninolytic) enzymes. In addition, other groups of fungi, such as species of Aspergillus and Trichoderma, have also been used for textile effluents treatment. The main aim of the present study was to requalify a Brazilian Trichoderma culture collection of 51 Trichoderma strains, isolated from different sources in Brazil and preserved in the oldest Latin-American Fungal Service Culture Collection, The Micoteca URM WDCM 804 (Recife, Brazil). Fungal isolates were re-identified through a polyphasic approach including macro- and micro-morphology and molecular biology, and screened for their capability to decolourise real effluents collected directly from storage tanks of a textile manufacture. Trichoderma atroviride URM 4950 presented the best performance on the dye decolourisation in real textile effluent and can be considered in a scale-up process at industrial level. Overall, the potential of Trichoderma strains in decolourising real textile dye present in textile effluent and the production of the oxidative enzymes Lac, LiP and MnP was demonstrated. Fungal strains are available in the collection e-catalogue to be further explored from the biotechnological point of view.

Neosartorya glabra polygalacturonase produced from fruit peels as inducers has the potential for application in passion fruit and apple juices

Summary Polygalacturonases are enzymes with the biotechnological potential for use in fruit juice clarification and for the enhancement of filtration efficiency. The aim of this work was to assess the production of polygalacturonase by the fungus Neosartorya glabra by means of solid-state and submerged fermentation using fruit peel residues as the carbon source, and also apply the enzyme in the clarification and decrease in viscosity of passion fruit and apple juices. The highest polygalacturonase (4.52 U/g/h) production was obtained by means of submerged fermentation in Vogel´s medium (1964) containing orange peel – Bahia variety (Citrus sinensis), at a concentration of 1.5% (w/v, dried mass) at 30-35°C for 72 h. The polygalacturonase of the crude extract presented optimal activity at 60°C and pH 5.5. The enzyme retained around 90% of the initial activity after 180 minutes at 40°C, and 50% of the initial activity after 150 minutes at 50°C. The enzyme was shown to be stable at acid pH values (3.0-6.5) after 120 minutes at 25oC. All these favourable enzymatic properties make the polygalacturonase attractive for potential uses in the industry of pectin-rich fruit juices, since the application of the crude extract to passion fruit (Passiflora edulis) juice caused an 80% reduction in viscosity and 75% decrease in light absorbance. In the processing of apple pulp juice (Malus domestica), there was a 50% reduction in viscosity and 78% decrease in light absorbance.

Polyphasic Approach Including MALDI-TOF MS/MS Analysis for Identification and Characterisation of Fusarium verticillioides in Brazilian Corn Kernels

Fusarium verticillioides is considered one of the most important global sources of fumonisins contamination in food and feed. Corn is one of the main commodities produced in the Northeastern Region of Brazil. The present study investigated potential mycotoxigenic fungal strains belonging to the F. verticillioides species isolated from corn kernels in 3 different Regions of the Brazilian State of Pernambuco. A polyphasic approach including classical taxonomy, molecular biology, MALDI-TOF MS and MALDI-TOF MS/MS for the identification and characterisation of the F. verticillioides strains was used. Sixty F. verticillioides strains were isolated and successfully identified by classical morphology, proteomic profiles of MALDI-TOF MS, and by molecular biology using the species-specific primers VERT-1 and VERT-2. FUM1 gene was further detected for all the 60 F. verticillioides by using the primers VERTF-1 and VERTF-2 and through the amplification profiles of the ISSR regions using the primers (GTG)₅ and (GACA)₄. Results obtained from molecular analysis shown a low genetic variability among these isolates from the different geographical regions. All of the 60 F. verticillioides isolates assessed by MALDI-TOF MS/MS presented ion peaks with the molecular mass of the fumonisin B1 (721.83 g/mol) and B2 (705.83 g/mol).

Effect of different carbon sources on decolourisation of an industrial textile dye under alkaline-saline conditions

White-rot fungal strains of Trametes versicolor and Phanerochaete chrysosporium were selected to study the decolourisation of the textile dye, Reactive Black 5, under alkaline-saline conditions. Free and immobilised T. versicolor cells showed 100 % decolourisation in the growth medium supplemented with 15 g l(-1) NaCl, pH 9.5 at 30 °C in liquid batch culture. Continuous culture experiments were performed in a fixed-bed reactor using free and immobilised T. versicolor cells and allowed 85-100 % dye decolourisation. The immobilisation conditions for the biomass and the additional supply of carbon sources improved the decolourisation performance during a long-term trial of 40 days. Lignin peroxidase, laccase and glyoxal oxidase activities were detected during the experiments. The laccase activity varied depending on carbon source utilized and glycerol-enhanced laccase activity compared to sucrose during extended growth.