Biochemical Characteristics of Microbial Enzymes and Their Significance from Industrial Perspectives

Caproic acid production from short-chained carboxylic acids produced by arrested anaerobic digestion of green waste: Development and optimization of a mixed caproic acid producing culture

Caproic acid is an important compound for producing a variety of chemicals and a potential precursor for Sustainable Aviation Fuels (SAF). This study aimed at developing a stable mixed culture producing caproic acid using short-chain carboxylic acids (SCCAs) derived from arrested anaerobic digestion (AAD) of green waste and optimizing chain elongation (CE) conditions. The results showed that the mixed culture was dominated by Clostridium sensu stricto 12 (53.09 %), optimally producing caproic acid at 37 °C, pH 7.20, with a 15 % inoculum concentration. Under these conditions, 75.59 % of the consumed electrons contributed to caproic acid formation. Gradual ethanol feeding in bioreactor experiments resulted in caproic acid titer of 13.36 g/L, with carbon conversion efficiency (CCE) of 81.91 % and electron transfer efficiency (ETE) of 76.39 %, surpassing batch experiments without gradual ethanol addition. These findings demonstrate that the effectiveness of a mixed culture can be improved, resulting in increased caproic acid production.

Comprehensive Insights into Microbial Lipases: Unveiling Structural Dynamics, Catalytic Mechanism, and Versatile Applications

Microbial lipases (MLs) are pivotal biocatalysts in lipid biotechnology due to their diverse enzymatic properties and substrate specificity, garnering significant research attention. This comprehensive review explores the significance of MLs in biocatalysis, providing insights into their structure, catalytic domain, and oxyanion hole. The catalytic mechanism is elucidated, highlighting the molecular processes driving their efficiency. The review delves into ML sources, spanning fungi, yeasts, bacteria, and actinomycetes, followed by a discussion on classification and characterization. Emphasizing the scattered findings in the literature, the paper consolidates the latest information on ML applications across various industries, from food and pharmaceuticals to biofuel production and the paper and pulp industry. The review captures the dynamic landscape of ML research, emphasizing their structure-function relationships and practical implications across diverse sectors.

Comprehensive review on the potential of ultrasound for blue food protein extraction, modification and impact on bioactive properties

Food security for the increasing global population is a significant challenge of the current times particularly highlighting the protein deficiencies. Plant-based proteins could be considered as alternate source of the protein. The digestibility and PDCASS value of these proteins are still a concern. Blue proteins, the new approach of utilizing the proteins from aquatic sources could be a possible solution as it contains all the essential amino acids. However, the conjugation of these proteins with fats and glycogen interferes with their techno-functional properties and consequently their applicability. The application of power ultrasound for extraction and modification of these proteins from aquatic sources to break open the cellular structure, increase extractability, alter the protein structure and consequently provide proteins with higher bioavailability and bioactive properties could be a potential approach for their effective utilization into food systems. The current review focuses on the application of power ultrasound when applied as extraction treatment, alters the sulphite and peptide bond and modifies protein to elevated digestibility. The degree of alteration is influenced by intensity, frequency, and exposure time. The extracted proteins will serve as a source of essential amino acids. Furthermore, modification will lead to the development of bioactive peptides with different functional applications. Numerous studies reveal that blue proteins have beneficial impacts on amino acid availability, and subsequently food security with higher PDCAAS values. In many cases, converted peptides give anti-hypertensive, anti-diabetic, and anti-oxidant activity. Therefore, researchers are concentrating on ultrasound-based extraction, modification, and application in food and pharmaceutical systems.

Application of microbial enzymes in medicine and industry: current status and future perspectives

Microbes are a major source of enzymes due to their ability to be mass-cultivated and genetically modified. Compared with plant and animal enzymes, microbial enzymes are more stable and active. Enzymes are generally classified into six classes based on their reaction, substrate specificity and mechanism of action. In addition to their application in medicine for treating diseases, these compounds are used as anti-inflammatory, thrombolytic and digestive agents. However, challenges such as immunogenicity, tissue specificity and short in vivo half-life make clinical trials complex. Enzymes are metabolic catalysts in industry and their production and extraction must be optimized to preserve profitability due to rising demand. The present review highlights the increasing importance of bacterial enzymes in industry and medicine and explores methods for their production, extraction and purification.

Interaction of Micro- and Nanoplastics with Enzymes: The Case of Carbonic Anhydrase

Microplastics (MPs) and nanoplastics (NPs) have emerged as significant environmental pollutants with potential detrimental effects on ecosystems and human health. Several studies indicate their interaction with enzymes; this topic represents a multifaceted research field encompassing several areas of interest from the toxicological and ecotoxicological impact of MPs and NPs on humans and wildlife to the biodegradation of plastics by microbial enzymes. This review aims to provide a critical analysis of the state-of-the-art knowledge of the interaction of MPs and NPs on the enzyme carbonic anhydrase (CA), providing recent insights, analyzing the knowledge gaps in the field, and drawing future perspectives of the research and its application. CA is a widespread and crucial enzyme in various organisms; it is critical for various physiological processes in animals, plants, and bacteria. It catalyzes the reversible hydration of CO2, which is essential for respiration, acid-base balance, pH homeostasis, ion transport, calcification, and photosynthesis. Studies demonstrate that MPs and NPs can inhibit CA activity with mechanisms including adsorption to the enzyme surface and subsequent conformational changes. In vitro and in silico studies highlight the role of electrostatic and hydrophobic interactions in these processes. In vivo studies present mixed results, which are influenced by factors like particle type, size, concentration, and organism type. Moreover, the potentiality of the esterase activity of CA for plastic degradation is discussed. The complexity of the interaction between CA and MPs/NPs underscores the need for further research to fully understand the ecological and health impacts of MPs and NPs on CA activity and expression and glimpses of the potentiality and perspectives in this field.

A review on endophytic bacteria of orchids: functional roles toward synthesis of bioactive metabolites for plant growth promotion and disease biocontrol

MAIN CONCLUSION

In this review, we have discussed the untapped potential of orchid endophytic bacteria as a valuable reservoir of bioactive metabolites, offering significant contributions to plant growth promotion and disease protection in the context of sustainable agriculture. Orchidaceae is one of the broadest and most diverse flowering plant families on Earth. Although the relationship between orchids and fungi is well documented, bacterial endophytes have recently gained attention for their roles in host development, vigor, and as sources of novel bioactive compounds. These endophytes establish mutualistic relationships with orchids, influencing plant growth, mineral solubilization, nitrogen fixation, and protection from environmental stress and phytopathogens. Current research on orchid-associated bacterial endophytes is limited, presenting significant opportunities to discover new species or genetic variants that improve host fitness and stress tolerance. The potential for extracting bioactive compounds from these bacteria is considerable, and optimization strategies for their sustainable production could significantly enhance their commercial utility. This review discusses the methods used in isolating and identifying endophytic bacteria from orchids, their diversity and significance in promoting orchid growth, and the production of bioactive compounds, with an emphasis on their potential applications in sustainable agriculture and other sectors.

Development of a Zn-Based Single-Atom Nanozyme for Efficient Hydrolysis of Glycosidic Bonds

Hydrolytic enzymes are essential components in second-generation biofuel technology and food fermentation processes. Nanozymes show promise for large-scale industrial applications as replacements for natural enzymes due to their distinct advantages. However, there remains a research gap concerning glycosidase nanozymes. In this study, a Zn-based single-atom nanozyme (ZnN4-900) is developed for efficient glycosidic bond hydrolysis in an aqueous solution. The planar structure of the class-porphyrin N4 material approximatively mimicked the catalytic centers of natural enzymes, facilitating oxidase-like (OXD-like) activity and promoting glycosidic bond cleavage. Theoretical calculations show that the Zn site can act as Lewis acids, attacking the C─O bond in glycosidic bonds. Additionally, ZnN4-900 has the ability to degrade starch and produce reducing sugars that increased yeast cell biomass by 32.86% and ethanol production by 14.56%. This catalyst held promising potential for enhancing processes in ethanol brewing and starch degradation industries.

A Critical Review on Immobilized Sucrose Isomerase and Cells for Producing Isomaltulose

Isomaltulose is a novel sweetener and is considered healthier than the common sugars, such as sucrose or glucose. It has been internationally recognized as a safe food product and holds vast potential in pharmaceutical and food industries. Sucrose isomerase is commonly used to produce isomaltulose from the substrate sucrose in vitro and in vivo. However, free cells/enzymes were often mixed with the product, making recycling difficult and leading to a significant increase in production costs. Immobilized cells/enzymes have the following advantages including easy separation from products, high stability, and reusability, which can significantly reduce production costs. They are more suitable than free ones for industrial production. Recently, immobilized cells/enzymes have been encapsulated using composite materials to enhance their mechanical strength and reusability and reduce leakage. This review summarizes the advancements made in immobilized cells/enzymes for isomaltulose production in terms of refining traditional approaches and innovating in materials and methods. Moreover, innovations in immobilized enzyme methods include cross-linked enzyme aggregates, nanoflowers, inclusion bodies, and directed affinity immobilization. Material innovations involve nanomaterials, graphene oxide, and so on. These innovations circumvent challenges like the utilization of toxic cross-linking agents and enzyme leakage encountered in traditional methods, thus contributing to enhanced enzyme stability.

Efficiency of thermostable purified laccase isolated from Physisporinus vitreus for azo dyes decolorization

Laccases are versatile biocatalysts that are prominent for industrial purposes due to their extensive substrate specificity. Therefore, this research investigated producing laccase from Physisporinus vitreus via liquid fermentation. The results revealed that veratryl alcohol (4mM) was the most effective inducer 7500U/L. On the other hand, Zn ions inhibited laccase production. The optimum carbon and nitrogen sources were glucose and tryptone by 5200 and 3300 U/L, respectively. Moreover, solvents exhibited various impacts on the enzyme activity at three different solvent concentrations (5%, 10% and 20%), however, it showed a highest activity at 5% of the investigated solvent. Ferric ions inhibited the enzyme activity. In addition, the enzyme has a high ability to decolorize azo dyes when using syringaldehyde as a mediator. The purified laccase from Physisporinus vitreus is a promising substance to be used for industrial and environmental applications due to its stability under harsh conditions and efficiency in decolorization of dyes.

A newly synthesized magnetic nanoparticle coated with glycidyl methacrylate monomer and 1,2,4-Triazole: Immobilization of α-Amylase from Bacillus licheniformis for more reuse, stability, and activity in the presence of H2O2

α-Amylase is a secretory enzyme commonly found in nature. The α-Amylase enzyme catalyzes the hydrolysis of α-D-(1,4)-glucosidic bonds in starch, glycogen, and polysaccharides. The chemical characterization of the composite carrier and the immobilized enzyme was performed, and the accuracy of the immobilization was confirmed by FTIR, SEM, and EDS analyses. The X-ray diffraction (XRD) analysis indicates that the magnetic nanoparticle retained its magnetic properties following the modification process. Based on the Thermogravimetric Analysis (TGA) outcomes, it was evident that the structural integrity of the FPT nanocomposite remained unchanged at 200°C. The optimal pH was determined to be 5.5, and no alteration was observed following the immobilization process. Purified α-amylases usually lose their activity rapidly above 50°C. In this study, Bacillus licheniformis α-Amylase enzyme was covalently immobilized on the newly synthesized magnetic composite carrier having more azole functional group. For novelty-designed immobilized enzymes, while there is no change in the pH and optimum operating temperature of the enzyme with immobilization, two essential advantages are provided to reduce enzyme costs: the storage stability and reusability are increased. Furthermore, our immobilization technique enhanced enzyme stability when comparing our immobilized enzyme with the reference enzyme in industrial applications. The activity of the immobilized enzyme was higher in presence of 1-3% H2O2.

Unlocking Flavor Potential Using Microbial β-Glucosidases in Food Processing

Aroma is among of the most important criteria that indicate the quality of food and beverage products. Aroma compounds can be found as free molecules or glycosides. Notably, a significant portion of aroma precursors accumulates in numerous food products as nonvolatile and flavorless glycoconjugates, termed glycosidic aroma precursors. When subjected to enzymatic hydrolysis, these seemingly inert, nonvolatile glycosides undergo transformation into fragrant volatiles or volatiles that can generate odor-active compounds during food processing. In this context, microbial β-glucosidases play a pivotal role in enhancing or compromising the development of flavors during food and beverage processing. β-glucosidases derived from bacteria and yeast can be utilized to modulate the concentration of particular aroma and taste compounds, such as bitterness, which can be decreased through hydrolysis by glycosidases. Furthermore, oral microbiota can influence flavor perception by releasing volatile compounds that can enhance or alter the perception of food products. In this review, considering the glycosidic flavor precursors present in diverse food and beverage products, we underscore the significance of glycosidases with various origins. Subsequently, we delve into emerging insights regarding the release of aroma within the human oral cavity due to the activity of oral microbial glycosidases.

Chicken viscera meal as substrate for the simultaneous production of antioxidant compounds and proteases by Aspergillus oryzae

The use of chicken waste can contribute to the development of new processes and obtaining molecules with high added value. An experimental design was applied to evaluate the effect of moisture, temperature, and inoculum size on the production of antioxidant peptides and proteases by A. oryzae IOC3999 through solid-state fermentation (SSF) of chicken viscera meal. As a result, the process conditions strongly influenced protease production and antioxidant activity of the fermented products. A global analysis of the results indicated that the most adequate conditions for SSF were (assay 9): 40% initial moisture, 30 °C as the incubation temperature, 5.05 × 106 spores/g as the inoculum size, and 48-h fermentation as the fermentation time. Under this condition, the antioxidant activities for the ABTS- and DPPH-radicals inhibition and ferric reducing antioxidant power (FRAP) methods were 376.16, 153.29, and 300.47 (µmol TE/g), respectively, and the protease production reached 428.22 U/g. Ultrafiltration of the crude extract obtained under optimized fermentation conditions was performed, and the fraction containing peptides with molecular mass lower than 3 kDa showed the highest antioxidant activity. The proteases were biochemically characterized and showed maximal activity at pH values ranging from 5.0 to 6.0 and a temperature of 50 °C. The thermodynamic parameters indicated that the process of thermal protease inactivation is not spontaneous (ΔG*d > 88.78 kJ/mol), increasing with temperature (ΔH*d 27.01-26.88 kJ/mol), and with reduced disorder in the system (ΔS*d <  - 197.74 kJ/mol) probably caused by agglomeration of partially denatured enzymes.

Strategy to combat biofilms: a focus on biofilm dispersal enzymes

Bacterial biofilms, which consist of three-dimensional extracellular polymeric substance (EPS), not only function as signaling networks, provide nutritional support, and facilitate surface adhesion, but also serve as a protective shield for the residing bacterial inhabitants against external stress, such as antibiotics, antimicrobials, and host immune responses. Biofilm-associated infections account for 65-80% of all human microbial infections that lead to serious mortality and morbidity. Tremendous effort has been spent to address the problem by developing biofilm-dispersing agents to discharge colonized microbial cells to a more vulnerable planktonic state. Here, we discuss the recent progress of enzymatic eradicating strategies against medical biofilms, with a focus on dispersal mechanisms. Particularly, we review three enzyme classes that have been extensively investigated, namely glycoside hydrolases, proteases, and deoxyribonucleases.

Role of organisms and their enzymes in the biodegradation of microplastics and nanoplastics: A review

Microplastic (MP) and Nanoplastic (NP) contamination have become a critical ecological concern due to their persistent presence in every aspect of the ecosystem and their potentially harmful effects. The current approaches to eradicate these wastes by burning up and dumping adversely impact the environment, while recycling has its own challenges. As a result, applying degradation techniques to eliminate these recalcitrant polymers has been a focus of scientific investigation in the recent past. Biological, photocatalytic, electrocatalytic, and, recently, nanotechnologies have been studied to degrade these polymers. Nevertheless, it is hard to degrade MPs and NPs in the environment, and these degradation techniques are comparatively inefficient and require further development. The recent research focuses on the potential use of microbes to degrade MPs and NPs as a sustainable solution. Therefore, considering the recent advancements in this important research field, this review highlights the utilization of organisms and enzymes for the biodegradation of the MPs and NPs with their probable degradation mechanisms. This review provides insight into various microbial entities and their enzymes for the biodegradation of MPs. In addition, owing to the lack of research on the biodegradation of NPs, the perspective of applying these processes to NPs degradation has also been looked at. Finally, a critical evaluation of the recent development and perspective for future research to improve the effective removal of MPs and NPs in the environment through biodegradation is also discussed.

A comprehensive review on the potential of microbial enzymes in multipollutant bioremediation: Mechanisms, challenges, and future prospects

Industrialization and other human activity represent significant environmental hazards. Toxic contaminants can harm a comprehensive platform of living organisms in their particular environments. Bioremediation is an effective remediation process in which harmful pollutants are eliminated from the environment using microorganisms or their enzymes. Microorganisms in the environment often create a variety of enzymes that can eliminate hazardous contaminants by using them as a substrate for development and growth. Through their catalytic reaction mechanism, microbial enzymes may degrade and eliminate harmful environmental pollutants and transform them into non-toxic forms. The principal types of microbial enzymes which can degrade most hazardous environmental contaminants include hydrolases, lipases, oxidoreductases, oxygenases, and laccases. Several immobilizations, genetic engineering strategies, and nanotechnology applications have been developed to improve enzyme performance and reduce pollution removal process costs. Until now, the practically applicable microbial enzymes from various microbial sources and their ability to degrade multipollutant effectively or transformation potential and mechanisms are unknown. Hence, more research and further studies are required. Additionally, there is a gap in the suitable approaches considering toxic multipollutants bioremediation using enzymatic applications. This review focused on the enzymatic elimination of harmful contaminants in the environment, such as dyes, polyaromatic hydrocarbons, plastics, heavy metals, and pesticides. Recent trends and future growth for effectively removing harmful contaminants by enzymatic degradation are also thoroughly discussed.

Tributyltin degrading microbial enzymes: A promising remediation approach

Brazil is one of the countries most impacted along the entire coastline by the presence of tributyltin (TBT), a biocide used in antifouling paints. Despite being banned since 2008, its use is still registered in the country, and it is possible to find recent inputs of this substance in places under the influence of shipyards, marinas, and fishing ports. In this study, a bacterium isolated from TBT-contaminated sediment from Santos and São Vicente Estuarine System (SESS) in Brazil, identified as Achromobacter sp., proved to be resistant to this compound. Furthermore, its crude enzymatic extract presented the ability to reduce up to 25 % of the initial TBT concentration in the liquid phase in 1 h, demonstrating to be a simple, fast, effective procedure and a potential tool for the environmental attenuation of TBT.

Estimate of the degradation potentials of cellulose, xylan, and chitin across global prokaryotic communities

Complex polysaccharides (e.g. cellulose, xylan, and chitin), the most abundant renewable biomass resources available on Earth, are mainly degraded by microorganisms in nature. However, little is known about the global distribution of the enzymes and microorganisms responsible for the degradation of cellulose, xylan, and chitin in natural environments. Through large-scale alignments between the sequences released by the Earth Microbiome Project and sequenced prokaryotic genomes, we determined that almost all prokaryotic communities have the functional potentials to degrade cellulose, xylan, and chitin. The median abundances of genes encoding putative cellulases, xylanases, and chitinases in global prokaryotic communities are 0.51 (0.17-1.01), 0.24 (0.05-0.57), and 0.33 (0.11-0.71) genes/cell, respectively, and the composition and abundance of these enzyme systems are environmentally varied. The taxonomic sources of the three enzymes are highly diverse within prokaryotic communities, and the main factor influencing the diversity is the community's alpha diversity index rather than gene abundance. Moreover, there are obvious differences in taxonomic sources among different communities, and most genera with degradation potentials are narrowly distributed. In conclusion, our analysis preliminarily depicts a panorama of cellulose-, xylan-, and chitin-degrading enzymatic systems across global prokaryotic communities.

Industrial applications of fungal lipases: a review

Fungal lipases (triacylglycerol acyl hydrolases EC 3.1.1.3) are significant industrial enzymes and have several applications in a number of industries and fields. Fungal lipases are found in several species of fungi and yeast. These enzymes are carboxylic acid esterases, categorized under the serine hydrolase family, and do not require any cofactor during the catalyzing of the reactions. It was also noticed that processes including the extraction and purification of lipases from fungi are comparatively easier and cheaper than other sources of lipases. In addition, fungal lipases have been classified into three chief classes, namely, GX, GGGX, and Y. Fungal lipases have applications not only in the hydrolysis of fats and oils (triglycerides) but are also involved in synthetic reactions such as esterification, acidolysis, alcoholysis, interesterification, and aminolysis. The production and activity of fungal lipases are highly affected by the carbon source, nitrogen source, temperature, pH, metal ions, surfactants, and moisture content. Therefore, fungal lipases have several industrial and biotechnological applications in many fields such as biodiesel production, ester synthesis, production of biodegradable biopolymers, formulations of cosmetics and personal care products, detergent manufacturing, degreasing of leather, pulp and paper production, textile industry, biosensor development, and drug formulations and as a diagnostic tool in the medical sector, biodegradation of esters, and bioremediation of wastewater. The immobilization of fungal lipases onto different carriers also helps in improving the catalytic activities and efficiencies of lipases by increasing thermal and ionic stability (in organic solvents, high pH, and temperature), being easy to recycle, and inducing the volume-specific loading of the enzyme onto the support, and thus, these features have proved to be appropriate for use as biocatalysts in different sectors.

Increasing protein stability by inferring substitution effects from high-throughput experiments

We apply a computational model, global multi-mutant analysis (GMMA), to inform on effects of most amino acid substitutions from a randomly mutated gene library. Using a high mutation frequency, the method can determine mutations that increase the stability of even very stable proteins for which conventional selection systems have reached their limit. As a demonstration of this, we screened a mutant library of a highly stable and computationally redesigned model protein using an in vivo genetic sensor for folding and assigned a stability effect to 374 of 912 possible single amino acid substitutions. Combining the top 9 substitutions increased the unfolding energy 47 to 69 kJ/mol in a single engineering step. Crystal structures of stabilized variants showed small perturbations in helices 1 and 2, which rendered them closer in structure to the redesign template. This case study illustrates the capability of the method, which is applicable to any screen for protein function.

Activity-Based Screening of Soil Samples from Nyingchi, Tibet, for Amylase-Producing Bacteria and Other Multifunctional Enzyme Capacities

Despite the interest in Tibetan soil as a promising source of functional enzymes with potential biotechnological applications, few studies have considered the screening and identification of amylase producing bacteria from Tibetan soil. Amylase has many applications in the food and feed industries, textile and biofuel production, and biomedical engineering. The area of amylase with specific properties is attracting growing attention because of its better application to various industrial conditions. This study aims to screen and identify amylase-producing strains from soil samples collected in Nyingchi, Tibet, and then explore whether the bacterial isolates are superior for unique enzymes. In this paper, a total of 127 amylase producing bacteria were isolated by activity-based screening of six Tibetan soil samples. The 16S rRNA gene survey then identified four major phyla, namely, firmicutes, bacteroidetes, proteobacteria, and actinobacteria, which were differentiated into twelve genera with a dominance of Bacillus (67.72%), followed by Pseudomonas (8.66%). Microbial diversity analysis revealed that the amylase-producing bacterial community of the Kadinggou forest soil sample showed the best variety (the Simpson index was 0.69 and the Shannon index was 0.85). The amylase activity assay of the bacterial isolates showed a mean of 0.66 U/mL at 28°C and pH 5.2. Based on the effect of temperatures and pHs on amylase activity, several bacterial isolates can produce thermophilic (50°C), psychrophilic (10°C), acidophilic (pH 4.2), and alkaliphilic (pH 10.2) amylases. Furthermore, four bacterial isolates were screened for amylase, protease, and esterase activities, which indicated multifunctional enzyme capacities. The present study is expected to contribute to our understanding of Tibetan microbial resources and their potential for scientific research and industrial applications.

Agro-Industrial Food Waste as a Low-Cost Substrate for Sustainable Production of Industrial Enzymes: A Critical Review

The grave environmental, social, and economic concerns over the unprecedented exploitation of non-renewable energy resources have drawn the attention of policy makers and research organizations towards the sustainable use of agro-industrial food and crop wastes. Enzymes are versatile biocatalysts with immense potential to transform the food industry and lignocellulosic biorefineries. Microbial enzymes offer cleaner and greener solutions to produce fine chemicals and compounds. The production of industrially important enzymes from abundantly present agro-industrial food waste offers economic solutions for the commercial production of value-added chemicals. The recent developments in biocatalytic systems are designed to either increase the catalytic capability of the commercial enzymes or create new enzymes with distinctive properties. The limitations of low catalytic efficiency and enzyme denaturation in ambient conditions can be mitigated by employing diverse and inexpensive immobilization carriers, such as agro-food based materials, biopolymers, and nanomaterials. Moreover, revolutionary protein engineering tools help in designing and constructing tailored enzymes with improved substrate specificity, catalytic activity, stability, and reaction product inhibition. This review discusses the recent developments in the production of essential industrial enzymes from agro-industrial food trash and the application of low-cost immobilization and enzyme engineering approaches for sustainable development.

Enzymatic hydrolysis of lignocellulosic biomass using a novel, thermotolerant recombinant xylosidase enzyme from Clostridium clariflavum: a potential addition for biofuel industry

The present study describes the cloning, expression, purification and characterization of the xylosidase gene (1650 bp) from a thermophilic bacterium Clostridium clariflavum into E. coli BL21 (DE3) using the expression vector pET-21a(+) for utilization in biofuel production. The recombinant xylosidase enzyme was purified to homogeneity by heat treatment and immobilized metal ion affinity chromatography. SDS-PAGE determined that the molecular weight of purified xylosidase was 60 kDa. This purified recombinant xylosidase showed its maximum activity at a temperature of 37 °C and pH 6.0. The purified recombinant xylosidase enzyme remains stable up to 90 °C for 4 h and retained 54.6% relative activity as compared to the control. The presence of metal ions such as Ca²⁺ and Mg²⁺ showed a positive impact on xylosidase enzyme activity whereas Cu²⁺ and Hg²⁺ inhibit its activity. Organic solvents did not considerably affect the stability of the purified xylosidase enzyme while DMSO and SDS cause the inhibition of enzyme activity. Pretreatment experiments were run in triplicate for 72 h at 30 °C using 10% NaOH. Saccharification experiment was performed by using 1% substrate (pretreated plant biomass) in citrate phosphate buffer of pH 6.5 loaded with 150 U mL⁻¹ of purified recombinant xylosidase enzyme along with ampicillin (10  μg mL⁻¹). Subsequent incubation was carried out at 50 °C and 100 rpm in a shaking incubator for 24 h. Saccharification potential of the recombinant xylosidase enzyme was calculated against both pretreated and untreated sugarcane bagasse and wheat straw as 9.63% and 8.91% respectively. All these characteristics of the recombinant thermotolerant xylosidase enzyme recommended it as a potential candidate for biofuel industry.

The present study describes the cloning, expression, purification and characterization of a xylosidase gene from Clostridium clariflavum into E. coli BL21 (DE3) using the expression vector pET-21a(+) for utilization in biofuel production.

Endophytic fungi: a potential source of industrial enzyme producers

Microbial enzymes have gained interest for their widespread use in various industries and medicine due to their stability, ease of production, and optimization. Endophytic fungi in plant tissues produce a wide range of secondary metabolites and enzymes, which exhibit a variety of biological activities. The present review illustrates promising applications of enzymes produced by endophytic fungi and discusses the characteristic features of the enzymes, application of the endophytic fungal enzymes in therapeutics, agriculture, food, and biofuel industries. Endophytic fungi producing ligninolytic enzymes have possible biotechnological applications in lignocellulosic biorefineries. The global market of industrially important enzymes, challenges, and future prospects are illustrated. However, the commercialization of endophytic fungal enzymes for industrial purposes is yet to be explored. The present review suggests that endophytic fungi can produce various enzymes and may become a novel source for upscaling the production of enzymes of industrial use.

Characterization and application of a crude bacterial protease to produce antioxidant hydrolysates from whey protein

Bacillus sp. CL14 crude protease was partially characterized and applied to obtain antioxidant whey protein isolate (WPI) hydrolysates. Optimal activity occurred at pH 9.0 and 60 °C. Ca²⁺, Mg²⁺, and Mn²⁺ (5 mM) enhanced activity (12-26%), whereas Co²⁺, Cu²⁺, Fe²⁺, and Zn²⁺ inhibited it (50-94%). At 1% (v/v), Tween 20 and Triton X-100 enhanced activities (21-27%), β-mercaptoethanol decreased it (15%), and dimethyl sulfoxide (DMSO) had no effect. Sodium dodecyl sulfate (SDS; 0.1%, w/v) increased activity by 36%. Complete inhibition by phenylmethylsulfonyl fluoride (PMSF), and 85% inhibition by ethylenediaminotetraacetic acid, indicates its serine protease character and the importance of cations for activity/stability. With 5 mM Ca²⁺, protease was optimally active at 65 °C and completely stable after 20 min at 40-55 °C. Crude protease preferentially hydrolyzed WPI and soy protein, followed by casein. WPI hydrolysis was then performed (55 °C, pH 9.0, 5 mM Ca²⁺) for 0-180 min. Contents of trichloroacetic acid (TCA)-soluble proteins in WPI hydrolysates (HWPI) increased from 29% (0 min) to 50-52% (60-180 min), accompanied by enhanced radical scavenging activity (14%, 0 min; ∼34%, 60-180 min) and Fe²⁺-chelating ability (56%, 0 min; ∼74%, 45-180 min). CL14 protease might represent an alternative biocatalyst to obtain antioxidant hydrolysates from WPI and, potentially, from other food proteins.

In silico characterization of the GH5-cellulase family from uncultured microorganisms: physicochemical and structural studies

BACKGROUND

Hydrolysis of cellulose-based biomass by cellulases produce fermented sugar for making biofuels, such as bioethanol. Cellulases hydrolyze the β-1,4-glycosidic linkage of cellulose and can be obtained from cultured and uncultured microorganisms. Uncultured microorganisms are a source for exploring novel cellulase genes through the metagenomic approach. Metagenomics concerns the extraction, cloning, and analysis of the entire genetic complement of a habitat without cultivating microbes. The glycoside hydrolase 5 family (GH5) is a cellulase family, as the largest group of glycoside hydrolases. Numerous variants of GH5-cellulase family have been identified through the metagenomic approach, including CelGH5 in this study. University-CoE-Research Center for Biomolecule Engineering, Universitas Airlangga successfully isolated CelGH5 from waste decomposition of oil palm empty fruit bunches (OPEFB) soil by metagenomics approach. The properties and structural characteristics of GH5-cellulases from uncultured microorganisms can be studied using computational tools and software.

RESULTS

The GH5-cellulase family from uncultured microorganisms was characterized using standard computational-based tools. The amino acid sequences and 3D-protein structures were retrieved from the GenBank Database and Protein Data Bank. The physicochemical analysis revealed the sequence length was roughly 332-751 amino acids, with the molecular weight range around 37-83 kDa, dominantly negative charges with pI values below 7. Alanine was the most abundant amino acid making up the GH5-cellulase family and the percentage of hydrophobic amino acids was more than hydrophilic. Interestingly, ten endopeptidases with the highest average number of cleavage sites were found. Another uniqueness demonstrated that there was also a difference in stability between in silico and wet lab. The II values indicated CelGH5 and ACA61162.1 as unstable enzymes, while the wet lab showed they were stable at broad pH range. The program of SOPMA, PDBsum, ProSA, and SAVES provided the secondary and tertiary structure analysis. The predominant secondary structure was the random coil, and tertiary structure has fulfilled the structure quality of QMEAN4, ERRAT, Ramachandran plot, and Z score.

CONCLUSION

This study can afford the new insights about the physicochemical and structural properties of the GH5-cellulase family from uncultured microorganisms. Furthermore, in silico analysis could be valuable in selecting a highly efficient cellulases for enhanced enzyme production.

Exogenous Enzymes as Zootechnical Additives in Animal Feed: A Review

Enzymes are widely used in the food industry. Their use as a supplement to the raw material for animal feed is a current research topic. Although there are several studies on the application of enzyme additives in the animal feed industry, it is necessary to search for new enzymes, as well as to utilize bioinformatics tools for the design of specific enzymes that work in certain environmental conditions and substrates. This will allow the improvement of the productive parameters in animals, reducing costs and making the processes more efficient. Technological needs have considered these catalysts as essential in many industrial sectors and research is constantly being carried out to optimize their use in those processes. This review describes the enzymes used in animal nutrition, their mode of action, their production and new sources of production as well as studies on different animal models to evaluate their effect on the productive performance intended for the production of animal feed.

Hybrid chemoenzymatic heterogeneous catalyst prepared in one step from zeolite nanocrystals and enzyme-polyelectrolyte complexes

The combination of inorganic heterogeneous catalysts and enzymes, in so-called hybrid chemoenzymatic heterogeneous catalysts (HCEHCs), is an attractive strategy to effectively run chemoenzymatic reactions. Yet, the preparation of such bifunctional materials remains challenging because both the inorganic and the biological moieties must be integrated in the same solid, while preserving their intrinsic activity. Combining an enzyme and a zeolite, for example, is complicated because the pores of the zeolite are too small to accommodate the enzyme and a covalent anchorage on the surface is often ineffective. Herein, we developed a new pathway to prepare a nanostructured hybrid catalyst built from glucose oxidase and TS-1 zeolite. Such hybrid material can catalyse the in situ biocatalytic formation of H₂O₂, which is subsequently used by the zeolite to trigger the epoxidation of allylic alcohol. Starting from an enzymatic solution and a suspension of zeolite nanocrystals, the hybrid catalyst is obtained in one step, using a continuous spray drying method. While enzymes are expectedly unable to resist the conditions used in spray drying (temperature, shear stress, etc.), we leverage on the preparation of "enzyme-polyelectrolyte complexes" (EPCs) to increase the enzyme stability. Interestingly, the use of EPCs also prevents enzyme leaching and appears to stabilize the enzyme against pH changes. We show that the one-pot preparation by spray drying gives access to hybrid chemoenzymatic heterogeneous catalysts with unprecedented performance in the targeted chemoenzymatic reaction. The bifunctional catalyst performs much better than the two catalysts operating as separate entities. We anticipate that this strategy could be used as an adaptable method to prepare other types of multifunctional materials starting from a library of functional nanobuilding blocks and biomolecules.

Molecular biology interventions for activity improvement and production of industrial enzymes

Metagenomics and directed evolution technology have brought a revolution in search of novel enzymes from extreme environment and improvement of existing enzymes and tuning them towards certain desired properties. Using advanced tools of molecular biology i.e. next generation sequencing, site directed mutagenesis, fusion protein, surface display, etc. now researchers can engineer enzymes for improved activity, stability, and substrate specificity to meet the industrial demand. Although many enzymatic processes have been developed up to industrial scale, still there is a need to overcome limitations of maintaining activity during the catalytic process. In this article recent developments in enzymes industrial applications and advancements in metabolic engineering approaches to improve enzymes efficacy and production are reviewed.

Bioconversion of agro-industry sourced biowaste into biomaterials via microbial factories - A viable domain of circular economy

Global increase in demand for food supply has resulted in surplus generation of wastes. What was once considered wastes, has now become a resource. Studies were carried out on the conversion of biowastes into wealth using methods such as extraction, incineration and microbial intervention. Agro-industry biowastes are promising sources of carbon for microbial fermentation to be transformed into value-added products. In the era of circular economy, the goal is to establish an economic system which aims to eliminate waste and ensure continual use of resources in a close-loop cycle. Biowaste collection is technically and economically practicable, hence it serves as a renewable carbon feedstock. Biowastes are commonly biotransformed into value-added materials such as bioethanol, bioplastics, biofuels, biohydrogen, biobutanol and biogas. This review reveals the recent developments on microbial transformation of biowastes into biotechnologically important products. This approach addresses measures taken globally to valorize waste to achieve low carbon economy. The sustainable use of these renewable resources is a positive approach towards waste management and promoting circular economy.

Purification and characterization of a novel extracellular, alkaline, thermoactive, and detergent-compatible lipase from Aeromonas caviae LipT51 for application in detergent industry

Lipase producer bacterium isolated from Erzurum was identified as Aeromonas caviae LipT51 (GenBank ID: MN818567.1) by 16S rDNA sequencing and conventional methods. Extracellular lipase was purified by ammonium sulphate precipitation, centrifugal filtration, and anion-exchange chromatography resulting in 6.1-fold purification with 28% final yield. Molecular weight was 31.6 kDa on SDS-PAGE. Lipase was stable over a broad range of pH (6-11) and temperature (25-70 °C), and showed optimum activity at pH 9 and 60 °C. Km and Vmax for pNPP hydrolysis were 0.88 mM and 34.2 U/mg protein, respectively. Ba²⁺, Ca²⁺, Co²⁺, Cu²⁺, Fe³⁺, and Mg²⁺ increased activity, while Mn²⁺, Mo²⁺, Ni²⁺, Zn²⁺, and other additives partially decreased. Activity and stability increased with laundry detergent and slightly decreased with handwash and dishwashing detergents. Alkaline and thermostable lipase from newly isolated A. caviae has been shown for the first time to be remarkably compatible with laundry detergent and improve washing performance by enhanced oil-stain removal.

Rhizopus oryzae Lipase, a Promising Industrial Enzyme: Biochemical Characteristics, Production and Biocatalytic Applications

Lipases are biocatalysts with a significant potential to enable a shift from current pollutant manufacturing processes to environmentally sustainable approaches. The main reason of this prospect is their catalytic versatility as they carry out several industrially relevant reactions as hydrolysis of fats in water/lipid interface and synthesis reactions in solvent-free or non-aqueous media such as transesterification, interesterification and esterification. Because of the outstanding traits of Rhizopus oryzae lipase (ROL), 1,3-specificity, high enantioselectivity and stability in organic media, its application in energy, food and pharmaceutical industrial sector has been widely studied. Significant advances have been made in the biochemical characterisation of ROL particularly in how its activity and stability are affected by the presence of its prosequence. In addition, native and heterologous production of ROL, the latter in cell factories like Escherichia coli, Saccharomyces cerevisiae and Komagataella phaffii (Pichia pastoris), have been thoroughly described. Therefore, in this review, we summarise the current knowledge about R. oryzae lipase (i) biochemical characteristics, (ii) production strategies and (iii) potential industrial applications.

Revisiting the scope and applications of food enzymes from extremophiles

Microorganisms from extreme environments tend to undergo various adaptations due to environmental conditions such as extreme pH, temperature, salinity, heavy metals, and solvents. Thus, they produce enzymes with unique properties and high specificity, making them useful industrially, particularly in the food industries. Despite these enzymes' remarkable properties, only a few instances can be reported for actual exploitation in the food industry. This review's objectives are to highlight the properties of these enzymes and their prospects in the food industry. First, an introduction to extremophilic organisms is presented, followed by the categories and application of food enzymes from extremophiles. Then, the unique structural features of extremozymes are shown. This review also covers the prospective applications of extremozymes in the food industry in a broader sense, including degradation of toxins, deconstruction of polymers into monomers, and catalysis of multistep processes. Finally, the challenges in bioprocessing of extremozymes and applications in food are presented. PRACTICAL APPLICATIONS: Enzymes are important players in food processing and preservation. Extremozymes, by their nature, are ideal for a broad range of food processing applications, particularly those that require process conditions of extreme pH, temperature, and salinity. As the global food industry grows, so too will grow the need to research and develop food products that are diverse, safe, healthy, and nutritious. There is also the need to produce food in a sustainable way that generates less waste or maximizes waste valorization. We anticipate that extremozymes can meet some of the research and development needs of the food industry.

Production and characterisation of lipase for application in detergent industry from a novel Pseudomonas helmanticensis HS6

The aim of this study was to explore novel source of lipase from biodiversity hot spot region of Sikkim with activity at broad temperature range for application in detergent industry. Among the isolates, Pseudomonas helmanticensis HS6 showed activity at wide range of temperatures was selected for lipase production. Statistical optimisation for enhanced production of lipase resulted in enhancement of lipase activity from 2.3 to 179.3 U/mg. Lipase was purified resulting in 18.78 fold purification, 5.58% yield and high specific activity of 3368 U/mg. The partially purified lipase was found to be active in wide range of temperature (5-80 °C) and pH (6-9), showing optimum activity at 50 °C at pH 7. Peptide sequences on mass spectrometric analysis of purified lipase showed similarity to lipase family protein of three species of Pseudomonas. Both crude and purified lipase retained residual activity of 40-80% after 3 h of incubation with commercial detergents suggesting its application in detergent industry.