Developmental strategies and regulation of cell-free enzyme system for ethanol production: a molecular prospective

Harnessing the power of bacterial laccases for xenobiotic degradation in water: A 10-year overview

Industrialization and population growth are leading to the production of significant amounts of sewage containing hazardous xenobiotic compounds. These compounds pose a threat to human and animal health, as well as the overall ecosystem. To combat this issue, chemical, physical, and biological techniques have been used to remove these contaminants from water bodies affected by human activity. Biotechnological methods have proven effective in utilizing microorganisms and enzymes, particularly laccases, to address this problem. Laccases possess versatile enzymatic characteristics and have shown promise in degrading different xenobiotic compounds found in municipal, industrial, and medical wastewater. Both free enzymes and crude enzyme extracts have demonstrated success in the biotransformation of these compounds. Despite these advancements, the widespread use of laccases for bioremediation and wastewater treatment faces challenges due to the complex composition, high salt concentration, and extreme pH often present in contaminated media. These factors negatively impact protein stability, recovery, and recycling processes, hindering their large-scale application. These issues can be addressed by focusing on large-scale production, resolving operation problems, and utilizing cutting-edge genetic and protein engineering techniques. Additionally, finding novel sources of laccases, understanding their biochemical properties, enhancing their catalytic activity and thermostability, and improving their production processes are crucial steps towards overcoming these limitations. By doing so, enzyme-based biological degradation processes can be improved, resulting in more efficient removal of xenobiotics from water systems. This review summarizes the latest research on bacterial laccases over the past decade. It covers the advancements in identifying their structures, characterizing their biochemical properties, exploring their modes of action, and discovering their potential applications in the biotransformation and bioremediation of xenobiotic pollutants commonly present in water sources.

Bacterial cellulose as a potential biopolymer in biomedical applications: a state-of-the-art review

Throughout history, natural biomaterials have benefited society. Nevertheless, in recent years, tailoring natural materials for diverse biomedical applications accompanied with sustainability has become the focus. With the progress in the field of materials science, novel approaches for the production, processing, and functionalization of biomaterials to obtain specific architectures have become achievable. This review highlights an immensely adaptable natural biomaterial, bacterial cellulose (BC). BC is an emerging sustainable biopolymer with immense potential in the biomedical field due to its unique physical properties such as flexibility, high porosity, good water holding capacity, and small size; chemical properties such as high crystallinity, foldability, high purity, high polymerization degree, and easy modification; and biological characteristics such as biodegradability, biocompatibility, excellent biological affinity, and non-biotoxicity. The structure of BC consists of glucose monomer units polymerized via cellulose synthase in β-1-4 glucan chains, creating BC nano fibrillar bundles with a uniaxial orientation. BC-based composites have been extensively investigated for diverse biomedical applications due to their similarity to the extracellular matrix structure. The recent progress in nanotechnology allows the further modification of BC, producing novel BC-based biomaterials for various applications. In this review, we strengthen the existing knowledge on the production of BC and BC composites and their unique properties, and highlight the most recent advances, focusing mainly on the delivery of active pharmaceutical compounds, tissue engineering, and wound healing. Further, we endeavor to present the challenges and prospects for BC-associated composites for their application in the biomedical field.

Biosynthesis of Linear Protein Nanoarrays Using the Flagellar Axoneme

Applications in biotechnology and synthetic biology often make use of soluble proteins, but there are many potential advantages of anchoring enzymes to a stable substrate, including stability and the possibility for substrate channeling. To avoid the necessity of protein purification and chemical immobilization, there has been growing interest in bio-assembly of protein-containing nanoparticles, exploiting the self-assembly of viral capsid proteins or other proteins that form polyhedral structures. However, these nanoparticles are limited in size, which constrains the packaging and the accessibility of the proteins. An axoneme, the insoluble protein core of the eukaryotic flagellum or cilium, is a highly ordered protein structure that can be several microns in length, orders of magnitude larger than other types of nanoparticles. We show that when proteins of interest are fused to specific axonemal proteins and expressed in living Chlamydomonas reinhardtii cells, they become incorporated into linear arrays, which have the advantages of high protein loading capacity and single-step purification with retention of biomass. The arrays can be isolated as membrane-enclosed vesicles or as exposed protein arrays. The approach is demonstrated for both a fluorescent protein and an enzyme (beta-lactamase), showing that incorporation into axonemes retains protein function in a stable, easily isolated array form.

Biochemistry, Synthesis, and Applications of Bacterial Cellulose: A Review

The potential of cellulose nanocomposites in the new-generation super-performing nanomaterials is huge, primarily in medical and environment sectors, and secondarily in food, paper, and cosmetic sectors. Despite substantial illumination on the molecular aspects of cellulose synthesis, various process features, namely, cellular export of the nascent polysaccharide chain and arrangement of cellulose fibrils into a quasi-crystalline configuration, remain obscure. To unleash its full potential, current knowledge on nanocellulose dispersion and disintegration of the fibrillar network and the organic/polymer chemistry needs expansion. Bacterial cellulose biosynthesis mechanism for scaled-up production, namely, the kinetics, pathogenicity, production cost, and product quality/consistency remain poorly understood. The bottom-up bacterial cellulose synthesis approach makes it an interesting area for still wider and promising high-end applications, primarily due to the nanosynthesis mechanism involved and the purity of the cellulose. This study attempts to identify the knowledge gap and potential wider applications of bacterial cellulose and bacterial nanocellulose. This review also highlights the manufacture of bacterial cellulose through low-cost substrates, that is, mainly waste from brewing, agriculture, food, and sugar industries as well as textile, lignocellulosic biorefineries, and pulp mills.

The Trend of Bacterial Nanocellulose Research Published in the Science Citation Index Expanded From 2005 to 2020: A Bibliometric Analysis

To gain insight into the trend of bacterial nanocellulose research, a bibliometric analysis was performed using the Science Citation Index Expanded database from 2005 to 2020. The study concentrated on the publication's performance in terms of annual outputs and citations, mainstream journals, categories of the Web of Sciences, leading countries, prominent institutions, and trends in research. Current research priorities and future trends were analyzed after summarizing the most commonly used keywords extracted from words in the paper title analysis, authors' keyword analysis, and KeyWords Plus. The findings revealed that the annual output in the form of scholarly articles on bacterial nanocellulose research steadily increased during the first quartile of the study period, followed by a very rapid increase in the last five-years of the study. Increasing mechanical strength would remain the main future focus of bacterial nanocellulose research to create its scope in different field of applications.

Production of Bacterial Cellulose from Acetobacter Species and Its Applications – A Review

Bacterial cellulose (BC) is a natural polymer secreted as a protective cell covering of certain bacterial species. In contrary to plant cellulose, BC possesses some unique features like high moisture-holding capacity, high durability, high liquid absorbing capabilities, biostability, and biodegradability, makes BC an excellent raw material in wide-ranging areas like biomedical, food, agriculture, paper, textile industries and electronics. The main objective of this review is to discuss various aspects of BC production (different sources for bacterial strain isolation, culture media and, its alternatives also major culture techniques). In addition, various applications of BC are also reviewed.

Perspective Applications and Associated Challenges of Using Nanocellulose in Treating Bone-Related Diseases

Bone serves to maintain the shape of the human body due to its hard and solid nature. A loss or weakening of bone tissues, such as in case of traumatic injury, diseases (e.g., osteosarcoma), or old age, adversely affects the individuals quality of life. Although bone has the innate ability to remodel and regenerate in case of small damage or a crack, a loss of a large volume of bone in case of a traumatic injury requires the restoration of bone function by adopting different biophysical approaches and chemotherapies as well as a surgical reconstruction. Compared to the biophysical and chemotherapeutic approaches, which may cause complications and bear side effects, the surgical reconstruction involves the implantation of external materials such as ceramics, metals, and different other materials as bone substitutes. Compared to the synthetic substitutes, the use of biomaterials could be an ideal choice for bone regeneration owing to their renewability, non-toxicity, and non-immunogenicity. Among the different types of biomaterials, nanocellulose-based materials are receiving tremendous attention in the medical field during recent years, which are used for scaffolding as well as regeneration. Nanocellulose not only serves as the matrix for the deposition of bioceramics, metallic nanoparticles, polymers, and different other materials to develop bone substitutes but also serves as the drug carrier for treating osteosarcomas. This review describes the natural sources and production of nanocellulose and discusses its important properties to justify its suitability in developing scaffolds for bone and cartilage regeneration and serve as the matrix for reinforcement of different materials and as a drug carrier for treating osteosarcomas. It discusses the potential health risks, immunogenicity, and biodegradation of nanocellulose in the human body.

Coupling and Regulation of Porous Carriers Using Plasma and Amination to Improve the Catalytic Performance of Glucose Oxidase and Catalase

Multiple enzyme systems are being increasingly used for their high-efficiency and co-immobilization is a key technology to lower the cost and improve the stability of enzymes. In this study, poly glycidyl methacrylate (PGMA) spheres were synthesized using suspension polymerization, and were used as a support to co-immobilize glucose oxidase (GOx) and catalase (CAT). Surface modification was carried out via a combination of plasma and amination to promote the properties of the catalyzer. The co-immobilized enzymes showed a more extensive range of optimum pH and temperature from 5.5 to 7.5 and 25 to 40°C, respectively, compared to free enzymes. Furthermore, the maximum activity and protein adsorption quantity of the co-immobilized enzymes reached 25.98 U/g and 6.07 mg/g, respectively. The enzymatic activity of the co-immobilized enzymes was maintained at ~70% after storage for 5 days and at 82% after three consecutive cycles, indicating that the immobilized material could be applied industrially.

Comparative Synthesis and Characterization of Bio-Cellulose from Local Waste and Cheap Resources

Background:

Bacterial cellulose (BC) has been extensively utilized in a wide range of applications specifically in the biomedical field thanks to its excellent physico-chemical and biological features. The major limitation restricting its application in certain areas is its high production cost. Its widespread applications demand exploration of alternative production media compared to the existing expensive ones. Herein, an effort has been made to utilize waste and cheaply available local resources including; waste (expired) orange juice (WOJ), sugarcane juice (SC) and coconut water (CW) as alternative media for BC production in comparison to the synthetic media (control).

Methods:

Waste and cheap resources were collected from the local market, screened filtered and optimized for the development of BC culture media. BC production from all media was observed under static cultivation for 10 days. The results indicated 2.75, 2.56, 3.32 and 1.68 g/L BC production that corresponded to 27.5%, 21.7 %, 20.1 % and 31.6 % sugar to BC conversion from control, WOJ, SC and CW media, respectively. Morphology and crystalline features of produced BC samples were observed through FE-SEM and XRD analysis. It was noteworthy that BC produced from all alternative sources indicated high water holding capabilities (WHC) and water retention time (WRT) that augment their applicability in drug delivery and wound healing applications.

Conclusion:

The BC production from cheap resources and its high physical, mechanical and biological properties can be of high interest for scaling up and commercialization of BC production processes. Furthermore, its liquidabsorbing capabilities and retention time can help in drug carrying and medical application.

Engineering Saccharomyces cerevisiae for production of simvastatin

Simvastatin is a semisynthetic cholesterol-lowering medication and one of the top-selling statins in the world. Currently, industrial production of simvastatin acid (SVA) is a multistep process starting from the natural product lovastatin. For this reason, there is significant interest in direct production of simvastatin from a microbial host. In this study, six heterologous biosynthetic genes were introduced into Saccharomyces cerevisiae and the acyl-donor dimethylbutyryl-S-methyl mercaptopropionate (DMB-SMMP) was added, resulting in initial production of 0.5 mg/L SVA. Switching the yeast strain from JHY686 to BJ5464-NpgA increased total polyketide production to over 60 mg/L and conversion from dihydromonacolin L acid to monacolin J acid (MJA) was increased from 60% to 90% by tuning the copy number of the P450 lovA. Increasing the media pH to 8.7 led to a further 10-fold increase in SVA production. Optimized chemical lysis of the cell walls in situ after maximum MJA production led to 55 mg/L SVA titer, representing nearly complete conversion from MJA and a 110-fold increase in titer from the initial SVA production strain. The yeast strains developed in this work can be used as an alternative production method for SVA, and the strategies employed can be broadly applied for heterologous production of other fungal polyketides and semisynthetic compounds in yeast.

A bilayered nanoshell for durable protection of single yeast cells against multiple, simultaneous hostile stimuli

Single cell surface engineering provides the most efficient, non-genetic strategy to enhance cell stability. However, it remains a huge challenge to improve cell stability in complex artificial environments. Here, a soft biohybrid interfacial layer is fabricated on individual living-cell surfaces by their exposure to a suspension of gold nanoparticles and l-cysteine to form a protecting functional layer to which porous silica layers were bound yielding pores with a diameter of 3.9 nm. The living cells within the bilayered nanoshells maintained high viability (96 ± 2%) as demonstrated by agar plating, even after five cycles of simultaneous exposure to high temperature (40 °C), lyticase and UV light. Moreover, yeast cells encapsulated in bilayered nanoshells were more recyclable than native cells due to nutrient storage in the shell.

A thermophilic cell-free cascade enzymatic reaction for acetoin synthesis from pyruvate

Acetoin (3-hydroxy-2-butanone) is an important bio-based platform chemical with wide applications. In vitro enzyme catalysed synthesis exhibits great feasibility in the production of chemicals with high purity. In the present work, a synthetic pathway involving a two-step continuous reaction was constructed in vitro for acetoin production from pyruvate at improved temperature. Thermostable candidates, acetolactate synthase (coAHASL1 and coAHASL2 from Caldicellulosiruptor owensensis OL) and α-acetolactate decarboxylase (bsALDC from Bacillus subtilis IPE5-4) were cloned, heterologously expressed, and characterized. All the enzymes showed maximum activities at 65–70 °C and pH of 6.5. Enzyme kinetics analysis showed that coAHASL1 had a higher activity but lower affinity against pyruvate than that of coAHASL2. In addition, the activities of coAHASL1 and bsALDC were promoted by Mn²⁺ and NADPH. The cascade enzymatic reaction was optimized by using coAHASL1 and bsALDC based on their kinetic properties. Under optimal conditions, a maximum concentration of 3.36 ± 0.26 mM acetoin was produced from 10 mM pyruvate after reaction for 24 h at 65 °C. The productivity of acetoin was 0.14 mM h⁻¹, and the yield was 67.80% compared with the theoretical value. The results confirmed the feasibility of synthesis of acetoin from pyruvate with a cell-free enzyme catalysed system at improved temperature.

Strategies for cost-effective and enhanced production of bacterial cellulose

Bacterial cellulose (BC) has received substantial attention because of its high purity, mechanical strength, crystallinity, liquid-absorbing capabilities, biocompatibility, and biodegradability etc. These properties allow BC to be used in various fields, especially in industries producing medical, electronic, and food products etc. A major discrepancy associated with BC is its high production cost, usually much higher than the plant cellulose. To address this limitations, researchers have developed several strategies for enhanced production of BC including the designing of advanced reactors and utilization of various carbon sources. Another promising approach is the production of BC from waste materials such as food, industrial, agricultural, and brewery wastes etc. which not only reduces the overall BC production cost but is also environment-friendly. Besides, exploration of novel and efficient BC producing microbial strains provides impressive boost to the BC production processes. To this end, development of genetically engineered microbial strains has proven useful for enhanced BC production. In this review, we have summarized major efforts to enhance BC production in order to make it a cost-effective biopolymer. This review can be of interest to researchers investigating strategies for enhanced BC production, as well as companies exploring pilot projects to scale up BC production for industrial applications.

Role of Recombinant DNA Technology to Improve Life

In the past century, the recombinant DNA technology was just an imagination that desirable characteristics can be improved in the living bodies by controlling the expressions of target genes. However, in recent era, this field has demonstrated unique impacts in bringing advancement in human life. By virtue of this technology, crucial proteins required for health problems and dietary purposes can be produced safely, affordably, and sufficiently. This technology has multidisciplinary applications and potential to deal with important aspects of life, for instance, improving health, enhancing food resources, and resistance to divergent adverse environmental effects. Particularly in agriculture, the genetically modified plants have augmented resistance to harmful agents, enhanced product yield, and shown increased adaptability for better survival. Moreover, recombinant pharmaceuticals are now being used confidently and rapidly attaining commercial approvals. Techniques of recombinant DNA technology, gene therapy, and genetic modifications are also widely used for the purpose of bioremediation and treating serious diseases. Due to tremendous advancement and broad range of application in the field of recombinant DNA technology, this review article mainly focuses on its importance and the possible applications in daily life.