Microbial production of multienzyme preparation from mosambi peel using Trichoderma asperellum

Fruit and vegetable wastes create unhygienic conditions and pose a environmental pollution. The utilization of such wastes as carbon sources for production of enzyme with microbial intervention could be an ecofriendly and profitable approach, apart from diminishing the waste load. The present investigation focused on the feasibility of using mosambi (Citrus limetta) peel as substrate for multienzyme production (pectinase, cellulase and amylase) through microbial intervention. Fifteen fungi were isolated from organic waste and screened in vitro their potential of biodegradation of mosambi peel through enzymes production. The best performing isolate was selected and identified as Trichoderma asperellum NG-125 (accession number-MW287256). Conditions viz. temperature, pH, incubation time and nutrient addition were optimized for efficient enzymes production. The maximum enzyme activity (U ml^-1 min^-1) of pectinase (595.7 ± 2.47), cellulase (497.3 ± 2.06) and amylase (440.9 ± 1.44) were observed at pH 5.5, incubation temperature of 30 °C after 10 days of fermentation. Moreover, macro-nutrients such as ammonium sulfate (0.1%) and potassium-di-hydrogen-ortho-phosphate (0.01%) further also enhanced the production of enzymes. The SDS-PAGE analysis of purified pectinase, cellulase and amylase using showed molecular mass of 43, 66 and 33 kDa, respectively. The enzyme retention activity (ERA) of aforesaid enzymes was also tested with four different natural fiber matrices viz., bagasse, rice husk, paddy straw and wheat straw. Among these, the maximum ERA was observed on bagasse matrix (pectinase-56.35%, cellulose-77.68% and amylase 59.54%). Enzymatic juice clarification yield obtained with test enzyme was 75.8%, as compared to 80.5% of commercial enzyme. The result indicates that T. asperellum may be exploited as multifaceted biocatalysis.

Insights on sustainable approaches for production and applications of value added products

The increasing demand for the development of sustainable strategies to utilize and process agro-industrial residues paves new paths for exploring innovative approaches in this area. Biotechnology based microbial transformations provide efficient, low cost and sustainable approaches for the production of value added products. The use of organic rich residues opens new avenues for the production of enzymes, pigments, biofuels, bioactive compounds, biopolymers etc. with vast industrial and therapeutic applications. Innovative technologies like strain improvement, enzyme immobilization, genome editing, morphological engineering, ultrasound/supercritical fluid/pulse electric field extraction, etc. can be employed. These will be helpful in achieving significant improvement in qualitative and quantitative parameters of the finished products. The global trend for the valorisation of biowaste has boosted the commercialization of these products which has transformed the markets by providing new investment opportunities. The upstream processing of raw materials using microbes poses a limitation in terms of product development and recovery which can be overcome by modifying the bioreactor design, physiological parameters or employing alternate technologies which will be discussed in this review. The other problems related to the processes include product stability, industrial applicability and cost competitiveness which needs to be addressed. This review comprehensively discusses the recent progress, avenues and challenges in the approaches aimed at valorisation of agro-industrial wastes along with possible opportunities in the bioeconomy.

Production of poly (l-lactide)-degrading enzyme by Actinomadura keratinilytica strain T16-1 under solid state fermentation using agricultural wastes as substrate

Poly (l-lactide) (PLLA) is an aliphatic polyester that can be obtained from renewable resources and degraded by various microorganisms. In previous reports, Actinomadura keratinilytica strain T16-1 demonstrated high ability to degrade PLLA under various conditions. PLLA-degrading enzyme production under solid state fermentation has been sparsely studied. PLLA-degrading enzyme production by A. keratinilytica strain T16-1 was investigated using agricultural wastes as substrate under solid state fermentation (SSF). Three agricultural wastes as soybean meal, cassava chips and duckweed were tested as substrates for PLLA-degrading enzyme production by statistical methods using mixture design. Results revealed that using duckweed as the substrate gave the highest enzyme production (138.66 ± 13.57 U/g dry substrate). Maximum enzyme activity of 391.24 ± 15.57 U/g dry substrate was obtained under 10 g duckweed, 10% inoculum size, 7 days of cultivation time, pH 7.0, 2.8% PLLA powder, and 60% moisture content at 45 °C. It can be concluded that duckweed is an inexpensive substrate, which reduces the costs of PLLA-degrading enzyme production, as an alternative to effective water weed management.

Microbial production and biotechnological applications of α-galactosidase

α-Galactosidase, (E.C. 3.2.1.22) is an exoglycosidase that target galactooligosaccharides such as raffinose, melibiose, stachyose and branched polysaccharides like galactomannans and galacto-glucomannans by catalysing the hydrolysis of α-1,6 linked terminal galactose residues. The enzyme has been isolated and characterized from microbial, plant and animal sources. This ubiquitous enzyme possesses physiological significance and immense industrial potential. Optimization of the growth conditions and efficient purification strategies can lead to a significant increase in the enzyme production. To boost commercial productivity, cloning of novel α-galactosidase genes and their heterologous expression in suitable host has gained popularity. Enzyme immobilization leads to its greater reutilization, superior thermostability, pH tolerance and increased activity. The enzyme is well explored in food industry in the removal of raffinose family oligosaccharides (RFOs) in soymilk and sugar crystallization process. It also improves animal feed quality and biomass processing. Applications of the enzyme is in the area of biomedicine includes therapeutic advances in treatment of Fabry disease, blood group conversion and removal of α-gal type immunogenic epitopes in xenotransplantation. With considerable biotechnological applications, this enzyme has been vastly commercialized and holds greater future prospects.

Diversity of cultivable fungal endophytes in Paullinia cupana (Mart.) Ducke and bioactivity of their secondary metabolites

Paullinia cupana is associated with a diverse community of pathogenic and endophytic microorganisms. We isolated and identified endophytic fungal communities from the roots and seeds of P. cupana genotypes susceptible and tolerant to anthracnose that grow in two sites of the Brazilian Amazonia forest. We assessed the antibacterial, antitumor and genotoxic activity in vitro of compounds isolated from the strains Trichoderma asperellum (1BDA) and Diaporthe phaseolorum (8S). In concert, we identified eight fungal species not previously reported as endophytes; some fungal species capable of inhibiting pathogen growth; and the production of antibiotics and compounds with bacteriostatic activity against Pseudomonas aeruginosa in both susceptible and multiresistant host strains. The plant genotype, geographic location and specially the organ influenced the composition of P. cupana endophytic fungal community. Together, our findings identify important functional roles of endophytic species found within the microbiome of P. cupana. This hypothesis requires experimental validation to propose management of this microbiome with the objective of promoting plant growth and protection.

Fungal Enzymes and Yeasts for Conversion of Plant Biomass to Bioenergy and High-Value Products

Fungi and fungal enzymes play important roles in the new bioeconomy. Enzymes from filamentous fungi can unlock the potential of recalcitrant lignocellulose structures of plant cell walls as a new resource, and fungi such as yeast can produce bioethanol from the sugars released after enzyme treatment. Such processes reflect inherent characteristics of the fungal way of life, namely, that fungi as heterotrophic organisms must break down complex carbon structures of organic materials to satisfy their need for carbon and nitrogen for growth and reproduction. This chapter describes major steps in the conversion of plant biomass to value-added products. These products provide a basis for substituting fossil-derived fuels, chemicals, and materials, as well as unlocking the biomass potential of the agricultural harvest to yield more food and feed. This article focuses on the mycological basis for the fungal contribution to biorefinery processes, which are instrumental for improved resource efficiency and central to the new bioeconomy. Which types of processes, inherent to fungal physiology and activities in nature, are exploited in the new industrial processes? Which families of the fungal kingdom and which types of fungal habitats and ecological specializations are hot spots for fungal biomass conversion? How can the best fungal enzymes be found and optimized for industrial use? How can they be produced most efficiently-in fungal expression hosts? How have industrial biotechnology and biomass conversion research contributed to mycology and environmental research? Future perspectives and approaches are listed, highlighting the importance of fungi in development of the bioeconomy.