Tannase production by Aspergillus aculeatus DBF9 through solid-state fermentation

Microbial Production of Value-added Products from Cashew Apples- an Economical Boost to Cashew Farmers

Cashew farming-considered as one of the major profit-making agricultural businesses-requires renewed practices in processing its products and by-products for sustained growth. The current review highlights the commercial potential of cashew apples by proposing value-addition strategies through microbial fermentation routes that can help garnering additional profit to the growers. The immense potential of cashew apples and pulp wastes generated after juice-extraction in producing a range of products through the fermentation process such as bioethanol, hydrolytic enzymes, lactic acid, biosurfactants, wine and Feni (an alcoholic beverage) is discussed. Furthermore, a case on the existing Feni-making practices in Goa, India is reviewed, and the need for upgrades in the processing methods for waste mitigation is emphasized. Based on the literature survey and from the gathered knowledge on cashew industries through visits to various cashew farming sites, it is strongly emphasized that a radical improvement in cashew farming is possible only through the adoption of holistic approaches in the cultivation and proper utilization of wastes and its management of cashew apples. Also, Feni production, which is the mainstay of India’s current cashew processing industry, requires major up-gradation in processing methods to improve its quality, marketability, and export potential.

A comprehensive review on tannase: Microbes associated production of tannase exploiting tannin rich agro-industrial wastes with special reference to its potential environmental and industrial applications

Microorganisms have been used for the production of various enzymes, including inducible tannase for various industrial and environmental applications. Tannases have lot of potential to convert hydrolysable tannins to gallic acid, which is one of the important industrial and therapeutic significant molecules whose demand is over 10000 tons per year. Tannins invariably occur in angiosperms, gymnosperms and pteridophytes, and predominantly present in various parts of plants such as, leaves, roots, bark and fruit. Furthermore, tannery effluents are frequently loaded with significant levels of tannic acid. Tannase can be effectively used to decrease tannin load in the toxic tannery effluent thus providing the opportunity to minimize the operational cost. Over the past three decades, tannase from microbial sources has been proposed for the degradation of natural tannins. The availability of various agro-industrial residues paves a way for maximum utilization of tannase production for the degradation of tannin and eventually the production of gallic acid. In this review, an illustrative and comprehensive account on tannase from microbial source for current day applications is presented. The present review emphasises on up-to-date microbial sources of tannases, biochemical properties, optimization of tannase production in solid state and submerged fermentation and its industrial and environmental applications.

Acurin A, a novel hybrid compound, biosynthesized by individually translated PKS- and NRPS-encoding genes in Aspergillus aculeatus

This work presents the identification and proposed biosynthetic pathway for a compound of mixed polyketide-nonribosomal peptide origin that we named acurin A. The compound was isolated from an extract of the filamentous fungus Aspergillus aculeatus, and its core structure resemble that of the mycotoxin fusarin C produced by several Fusarium species. Based on bioinformatics in combination with RT-qPCR experiments and gene-deletion analysis, we identified a biosynthetic gene cluster (BGC) in A. aculeatus responsible for the biosynthesis of acurin A. Moreover, we were able to show that a polyketide synthase (PKS) and a nonribosomal peptide synthetase (NRPS) enzyme separately encoded by this BGC are responsible for the synthesis of the PK-NRP compound, acurin A, core structure. In comparison, the production of fusarin C is reported to be facilitated by a linked PKS-NRPS hybrid enzyme. Phylogenetic analyses suggest the PKS and NRPS in A. aculeatus resulted from a recent fission of an ancestral hybrid enzyme followed by gene duplication. In addition to the PKS- and NRPS-encoding genes of acurin A, we show that six other genes are influencing the biosynthesis including a regulatory transcription factor. Altogether, we have demonstrated the involvement of eight genes in the biosynthesis of acurin A, including an in-cluster transcription factor. This study highlights the biosynthetic capacity of A. aculeatus and serves as an example of how the CRISPR/Cas9 system can be exploited for the construction of fungal strains that can be readily engineered.

Production of Enzymes From Agricultural Wastes and Their Potential Industrial Applications

Enzymatic hydrolysis is the significant technique for the conversion of agricultural wastes into valuable products. Agroindustrial wastes such as rice bran, wheat bran, wheat straw, sugarcane bagasse, and corncob are cheapest and plentifully available natural carbon sources for the production of industrially important enzymes. Innumerable enzymes that have numerous applications in industrial processes for food, drug, textile, and dye use have been produced from different types of microorganisms from agricultural wastes. Utilization of agricultural wastes offers great potential for reducing the production cost and increasing the use of enzymes for industrial purposes. This chapter focuses on economic production of actinobacterial enzymes from agricultural wastes to make a better alternative for utilization of biomass generated in million tons as waste annually.

Tannase Production by Penicillium Atramentosum KM under SSF and its Applications in Wine Clarification and Tea Cream Solubilization

Tannin acyl hydrolase commonly known as tannase is an industrially important enzyme having a wide range of applications, so there is always a scope for novel tannase with better characteristics. A newly isolated tannase-yielding fungal strain identified as Penicillium atramentosum KM was used for tannase production under solid-state fermentation (SSF) using different agro residues like amla (Phyllanthus emblica), ber (Zyzyphus mauritiana), jamun (Syzygium cumini), Jamoa (Eugenia cuspidate) and keekar (Acacia nilotica) leaves. Among these substrates, maximal extracellular tannase production i.e. 170.75 U/gds and 165.56 U/gds was obtained with jamun and keekar leaves respectively at 28ºC after 96 h. A substrate to distilled water ratio of 1:2 (w/v) was found to be the best for tannase production. Supplementation of sodium nitrate (NaNO₃) as nitrogen source had enhanced tannase production both in jamun and keekar leaves. Applications of the enzyme were studied in wine clarification and tea cream solubilization. It resulted in 38.05% reduction of tannic acid content in case of jamun wine, 43.59% reduction in case of grape wine and 74% reduction in the tea extract after 3 h at 35°C.

Novel strategies for upstream and downstream processing of tannin acyl hydrolase

Tannin acyl hydrolase also referred as tannase is an enzyme with important applications in several science and technology fields. Due to its hydrolytic and synthetic properties, tannase could be used to reduce the negative effects of tannins in beverages, food, feed, and tannery effluents, for the production of gallic acid from tannin-rich materials, the elucidation of tannin structure, and the synthesis of gallic acid esters in nonaqueous media. However, industrial applications of tannase are still very limited due to its high production cost. Thus, there is a growing interest in the production, recovery, and purification of this enzyme. Recently, there have been published a number of papers on the improvement of upstream and downstream processing of the enzyme. These papers dealt with the search for new tannase producing microorganisms, the application of novel fermentation systems, optimization of culture conditions, the production of the enzyme by recombinant microorganism, and the design of efficient protocols for tannase recovery and purification. The present work reviews the state of the art of basic and biotechnological aspects of tannin acyl hydrolase, focusing on the recent advances in the upstream and downstream processing of the enzyme.

Involvement of Physical Parameters in Medium Improvement for Tannase Production by Aspergillus niger FETL FT3 in Submerged Fermentation

Aspergillus niger FETL FT3, a local extracellular tannase producer strain that was isolated from one of dumping sites of tannin-rich barks of Rhizophora apiculata in Perak, Malaysia. This fungus was cultivated in 250 mL Erlenmeyer flask under submerged fermentation system. Various physical parameters were studied in order to maximize the tannase production. Maximal yield of tannase production, that is, 2.81 U per mL was obtained on the fourth day of cultivation when the submerged fermentation was carried out using liquid Czapek-Dox medium containing (percent; weight per volume) 0.25% NaNO₃, 0.1% KH₂PO₄, 0.05% MgSO₄ ·7H₂O, 0.05% KCl, and 1.0% tannic acid. The physical parameters used initial medium pH of 6.0, incubation temperature of 30°C, agitation speed of 200 rpm and inoculums size of 6 × 10⁶ spores/ ml. This research has showed that physical parameters were influenced the tannase production by the fungus with 156.4 percent increment.

Exploitation of biological wastes for the production of value-added products under solid-state fermentation conditions

Biological wastes contain several reusable substances of high value such as soluble sugars and fibre. Direct disposal of such wastes to soil or landfill causes serious environmental problems. Thus, the development of potential value-added processes for these wastes is highly attractive. These biological wastes can be used as support-substrates in solid-state fermentation (SSF) to produce industrially relevant metabolites with great economical advantage. In addition, it is an environmentally friendly method of waste management. This paper reviews the reutilization of biological wastes for the production of value-added products using the SSF technique.