Microalgae as Contributors to Produce Biopolymers

Biopolymers are very favorable materials produced by living organisms, with interesting properties such as biodegradability, renewability, and biocompatibility. Biopolymers have been recently considered to compete with fossil-based polymeric materials, which rase several environmental concerns. Biobased plastics are receiving growing interest for many applications including electronics, medical devices, food packaging, and energy. Biopolymers can be produced from biological sources such as plants, animals, agricultural wastes, and microbes. Studies suggest that microalgae and cyanobacteria are two of the promising sources of polyhydroxyalkanoates (PHAs), cellulose, carbohydrates (particularly starch), and proteins, as the major components of microalgae (and of certain cyanobacteria) for producing bioplastics. This review aims to summarize the potential of microalgal PHAs, polysaccharides, and proteins for bioplastic production. The findings of this review give insight into current knowledge and future direction in microalgal-based bioplastic production considering a circular economy approach. The current review is divided into three main topics, namely (i) the analysis of the main types and properties of bioplastic monomers, blends, and composites; (ii) the cultivation process to optimize the microalgae growth and accumulation of important biobased compounds to produce bioplastics; and (iii) a critical analysis of the future perspectives on the field.     

Marine Microbial-Derived Resource Exploration: Uncovering the Hidden Potential of Marine Carotenoids

Microbes in marine ecosystems are known to produce secondary metabolites. One of which are carotenoids, which have numerous industrial applications, hence their demand will continue to grow. This review highlights the recent research on natural carotenoids produced by marine microorganisms. We discuss the most recent screening approaches for discovering carotenoids, using in vitro methods such as culture-dependent and culture-independent screening, as well as in silico methods, using secondary metabolite Biosynthetic Gene Clusters (smBGCs), which involves the use of various rule-based and machine-learning-based bioinformatics tools. Following that, various carotenoids are addressed, along with their biological activities and metabolic processes involved in carotenoids biosynthesis. Finally, we cover the application of carotenoids in health and pharmaceutical industries, current carotenoids production system, and potential use of synthetic biology in carotenoids production.     

Life Cycle Assessment and sustainability methodologies for assessing industrial crops, processes and end products

Providing food, energy and materials for the rising global population is a challenge which is compounded by increased pressure on natural resources such as land, water and fossil sources of raw materials. Greenhouse gas (GHG) emissions from human activities have increased with industrial development and population expansion, and it is anticipated that resulting climate change might further limit agricultural productivity, through changes to weather patterns and global availability/distribution of agriculturally productive land. Growing crops as feedstocks for industrial uses is seen as one way of reducing GHG emissions and dependency on fossil resources. However, determining the extent to which the development of crops for industrial use will effect GHG balances and provide for a more energy efficient manufacturing system requires the development and use of appropriate calculation methodologies.Research at the Porter Institute has identified over 250 different scenarios for bioenergy production systems using commodity crops. In order to rationalise this complexity and diversity, a modular approach to Life Cycle Assessment (LCA) and sustainability analysis has been taken. This allows characterisation of discrete sections of supply chains and enables comparisons to be made between different crop production systems, different process systems and different end product uses. The purposes of this paper are to introduce the concepts of biofuel GHG and sustainability metrics, to introduce the approach taken by our organization and to use the example of UK grown willow in a lignocellulosic ethanol production system to demonstrate how GHG emission outcomes can be reviewed for “new” crops and technologies.The results show a range of variation, in both growing and process systems and how outcomes such as energy and GHG balances can be affected by various activities.LCA methodologies provide data to inform governments and industry of the potential specific supply chains may have for energy and GHG saving. However, methodological approaches can also affect assessment outcomes. Unresolved issues in LCA methodology must also be evaluated e.g. impacts resulting from land use change. Sustainability assessments of crop growing systems, irrespective of the end use, also assist in the assessment of environmental impacts of supply chains. However, it is critical that data continue to be collected, analysed and reviewed, to ensure that the most appropriate crops are grown and processed for the most appropriate end use.     

Phylogeny and Biogeography of Cyanobacteria and Their Produced Toxins

Phylogeny is an evolutionary reconstruction of the past relationships of DNA or protein sequences and it can further be used as a tool to assess population structuring, genetic diversity and biogeographic patterns. In the microbial world, the concept that everything is everywhere is widely accepted. However, it is much debated whether microbes are easily dispersed globally or whether they, like many macro-organisms, have historical biogeographies. Biogeography can be defined as the science that documents the spatial and temporal distribution of a given taxa in the environment at local, regional and continental scales. Speciation, extinction and dispersal are proposed to explain the generation of biogeographic patterns. Cyanobacteria are a diverse group of microorganisms that inhabit a wide range of ecological niches and are well known for their toxic secondary metabolite production. Knowledge of the evolution and dispersal of these microorganisms is still limited, and further research to understand such topics is imperative. Here, we provide a compilation of the most relevant information regarding these issues to better understand the present state of the art as a platform for future studies, and we highlight examples of both phylogenetic and biogeographic studies in non-symbiotic cyanobacteria and cyanotoxins.     

Influence of reducing agents on properties of thermo-molded wheat gluten bioplastics

The present work aims to study the influence of reducing agents of sodium bisulfite, sodium sulfite and thioglycolic acid on the equibiaxial extensional deformation of glycerol plasticized wheat gluten and the properties of gluten bioplastics thermo-molded at 125 °C. Moisture absorption, weight loss and water uptake, uniaxial tensile properties (Young's modulus, tensile strength, elongation at break and tensile set), and morphology observations were performed to characterize the physical properties of the thermo-molded gluten bioplastics. The results showed that reducing agents facilitated the viscous flow and restrained the elastic recovery of the plasticized gluten while not hindering the crosslinking reaction of gluten proteins during thermo-molding. On the contrary, reducing agents do not significantly influence moisture absorption, Young's modulus, tensile strength and the morphology of the gluten bioplastics thermo-molded at 125 °C. It is shown that reducing agents are highly effective for tailoring the flow viscosity of the plasticized gluten dough and the mechanical properties of thermo-molded gluten bioplastics.     

Influence of reducing agents on properties of thermo-molded wheat gluten bioplastics

The present work aims to study the influence of reducing agents of sodium bisulfite, sodium sulfite and thioglycolic acid on the equibiaxial extensional deformation of glycerol plasticized wheat gluten and the properties of gluten bioplastics thermo-molded at 125 °C. Moisture absorption, weight loss and water uptake, uniaxial tensile properties (Young's modulus, tensile strength, elongation at break and tensile set), and morphology observations were performed to characterize the physical properties of the thermo-molded gluten bioplastics. The results showed that reducing agents facilitated the viscous flow and restrained the elastic recovery of the plasticized gluten while not hindering the crosslinking reaction of gluten proteins during thermo-molding. On the contrary, reducing agents do not significantly influence moisture absorption, Young's modulus, tensile strength and the morphology of the gluten bioplastics thermo-molded at 125 °C. It is shown that reducing agents are highly effective for tailoring the flow viscosity of the plasticized gluten dough and the mechanical properties of thermo-molded gluten bioplastics.     

Marine Microbial Fibrinolytic Enzymes: An Overview of Source,Production, Biochemical Properties and Thrombolytic Activity

Cardiovascular diseases (CVDs) have emerged as a major threat to global health resulting in a decrease in life expectancy with respect to humans. Thrombosis is one of the foremost causes of CVDs, and it is characterized by the unwanted formation of fibrin clots. Recently, microbial fibrinolytic enzymes due to their specific features have gained much more attention than conventional thrombolytic agents for the treatment of thrombosis. Marine microorganisms including bacteria and microalgae have the significant ability to produce fibrinolytic enzymes with improved pharmacological properties and lesser side effects and, hence, are considered as prospective candidates for large scale production of these enzymes. There are no studies that have evaluated the fibrinolytic potential of marine fungal-derived enzymes. The current review presents an outline regarding isolation sources, production, features, and thrombolytic potential of fibrinolytic biocatalysts from marine microorganisms identified so far.     

Preparation and properties of thermo-molded bioplastics of glutenin-rich fraction

The present work aims to prepare bioplastics from a glutenin-rich fraction; that is, the gluten residue insoluble in 70% (v/v) ethanol. The influence of reducing agents of sodium bisulfite, sodium sulfite and thioglycolic acid on the properties of the glycerol plasticized doughs and the cross-linked bioplastics were investigated. The results showed that reducing agents can be applied to reduce the Young's modulus of the plasticized dough and to improve the Young's modulus of the cross-linked bioplastics. Moisture absorption, weight loss in water, tensile strength, elongation at break and tensile set were studied to characterize the physical properties of the cross-linked bioplastics.     

茎纤维生物提取和发酵燃料乙醇技术研究进展

利用微生物及其酶技术，提取茎纤维和发酵燃料乙醇是解决环境污染严重与能源短缺的有效途径之一。本文通过对茎纤维生物提取和发酵燃料乙醇的国内外研究现状和最新进展进行综述，针对茎纤维生物提取和发酵燃料乙醇研究的问题，提出了积极引进国外先进技术；建立规范化的生物脱胶示范工厂。开展生物脱胶精干麻的梳纺工艺技术研究和低木质素和高纤维素能源品种的选育及其高效生产技术研究等建议。     

Morphology and mechanical properties of thermo-molded bioplastics based on glycerol-plasticized wheat gliadins

Glycerol-plasticized wheat gliadin bioplastics were prepared through thermo-molding method. The effect of glycerol content on the morphology and the mechanical properties of wheat gliadin bioplastics was studied. Morphology, tensile properties (tensile strength and elongation at break), dynamic mechanical properties and rheological properties were evaluated in relation to glycerol content. Experimental results reveal that the morphology, the glass transition temperatures (T_g) of both the gliadin-rich and the glycerol-rich domains and the tensile properties are closely linked to the glycerol content. The time–temperature superposition (TTS) fails to be applied to the dynamic loss modulus G″ (all temperatures) and the dynamic storage modulus G′ (above 80 °C) of wheat gliadin bioplastics.     

兽用抗生素在水环境中的残留特征及有害效应

根据国内外已有的研究报道，综述四环素、磺胺类等典型兽用抗生素的使用现状，介绍水环境中兽用抗生素的污染特征及其微生物学效应。针对中国的具体情况，提出未来兽用抗生素研究重点和发展方向。     

Examination of marine-based cultivation of three demosponges for acquiring bioactive marine natural products

Marine sponges are an extremely rich and important source of natural products. Mariculture is one solution to the so-called "supply problem" that often hampers further studies and development of novel compounds from sponges. We report the extended culture (767 days) at sea in depths of 10 and 20 m of three sponge species: Negombata magnifica, Amphimedon chloros and Theonella swinhoei that produce latrunculin-B, halitoxin and swinholide-A, respectively. Since sponge-associated microorganisms may be the true producers of many of the natural products found in sponges and also be linked to the health of the sponges, we examined the stability of the bacterial communities in cultured versus wild sponges. Growth rate of the sponges (ranging from 308 to 61 and -19 (%)(year(-1)) in N. magnifica, A. chloros and T. swinhoei, respectively) differed significantly between species but not between the two depths at which the species were cultivated. Survivorship varied from 96% to 57%. During culture all species maintained the content of the desired natural product. Denaturing gradient gel electrophoresis analysis of the sponge-associated bacterial consortia revealed that differences existed between cultured and wild sponges in T. swinhoei and A. chloros but the communities remained quite stable in N. magnifica. The cultivation technique for production of natural products was found to be most appropriate for N. magnifica, while for T. swinhoei and A. chloros it was less successful, because of poorer growth and survival rates and shifts in their bacterial consortia.     

Haloferax mediterranei Cells as C50 Carotenoid Factories

Haloarchaea produce C50 carotenoids such as bacterioruberin, which are of biotechnological in-terest. This study aimed to analyze the effect of different environmental and nutritional conditions on the cellular growth and dynamics of carotenoids accumulation in Haloferax mediterranei. The maximum production of carotenoids (40 µg·mL⁻¹) was obtained during the stationary phase of growth, probably due to nutrient-limiting conditions (one-step culture). By seven days of culture, 1 mL culture produced 22.4 mg of dry weight biomass containing 0.18 % (w/w) of carotenoids. On the other hand, carbon-deficient cultures (low C/N ratio) were observed to be optimum for C50 bacterioruberin production by Hfx. mediterranei, but negatively affected the growth of cells. Thus, a two-steps process was evaluated for optimum carotenoids yield. In the first step, a nutri-ent-repleted culture medium enabled the haloarchaea to produce biomass, while in the second step, the biomass was incubated under osmotic stress and in a carbon-deficient medium. Under the conditions used, the obtained biomass contained 0.27% (w/w) of carotenoids after seven days, which accounts for 58.49 µg·mL⁻¹ of carotenoids for a culture with turbidity 14.0.     

N-acetylglucosamine: production and applications

N-Acetylglucosamine (GlcNAc) is a monosaccharide that usually polymerizes linearly through (1,4)-β-linkages. GlcNAc is the monomeric unit of the polymer chitin, the second most abundant carbohydrate after cellulose. In addition to serving as a component of this homogeneous polysaccharide, GlcNAc is also a basic component of hyaluronic acid and keratin sulfate on the cell surface. In this review, we discuss the industrial production of GlcNAc, using chitin as a substrate, by chemical, enzymatic and biotransformation methods. Also, newly developed methods to obtain GlcNAc using glucose as a substrate in genetically modified microorganisms are introduced. Moreover, GlcNAc has generated interest not only as an underutilized resource but also as a new functional material with high potential in various fields. Here we also take a closer look at the current applications of GlcNAc, and several new and cutting edge approaches in this fascinating area are thoroughly discussed.     

渥堆过程中主要微生物对云南普洱茶品质形成的研究

对云南普洱茶渥堆过程中的微生物研究表明：主要微生物有黑曲霉（Aspergillus niger）、青霉属（Penicllium）、根霉属（Rhizopus）、灰绿曲霉（Aspergillus gloucus）、酵母属（Saccharomyces）、土生曲霉（Aspergillus terreus）、白曲霉（Aspergillus candidus）、细菌类（Bacterium）。其中黑曲霉最多,它能产生葡萄糖淀粉酶、果胶酶、纤维素酶等;酵母次之,除它本身含有极丰富的对人体有益的营养物质、丰富的酶系统和生理活性物质外,酵母菌还能代谢产生维生素B₁、B_2、、维生素C^[1]等物质。这些微生物对普洱茶品质形成都直接或间接地起作用。     

Rheological and mechanical properties of bioplastics based on gluten- and glutenin-rich fractions

The present work aims to investigate the dynamic rheology at small strains and the equibiaxial extensional deformation at large strain of the glycerol plasticized dough of gluten- and glutenin-rich fractions and their mixture as well as the uniaxial tension deformation behavior of the compression molded bioplastics. The influence of glutenin-to-gluten ratio (GGR) on the rheological properties of the glycerol plasticized doughs and the crosslinked bioplastics were investigated. The results showed that the glutenin dough exhibits higher moduli and lower loss factor and equibiaxial deformability in comparison with the gluten dough. Addition of a glutenin-rich fraction to the gluten dough can improve elasticity at small deformation and extensional deformational stress at large deformations but result in reductions in extensibility of the compression molded bioplastics.     

Rheological and mechanical properties of bioplastics based on gluten- and glutenin-rich fractions

The present work aims to investigate the dynamic rheology at small strains and the equibiaxial extensional deformation at large strain of the glycerol plasticized dough of gluten- and glutenin-rich fractions and their mixture as well as the uniaxial tension deformation behavior of the compression molded bioplastics. The influence of glutenin-to-gluten ratio (GGR) on the rheological properties of the glycerol plasticized doughs and the crosslinked bioplastics were investigated. The results showed that the glutenin dough exhibits higher moduli and lower loss factor and equibiaxial deformability in comparison with the gluten dough. Addition of a glutenin-rich fraction to the gluten dough can improve elasticity at small deformation and extensional deformational stress at large deformations but result in reductions in extensibility of the compression molded bioplastics.     

珠三角主要工业区周边蔬菜产地土壤重金属污染调查分析

采集珠三角地区主要工业区周边蔬菜产地土壤,研究土壤中铅(Pb)、镉(Cd)、汞(Hg)、砷(As)、铬(Cr)5种重金属的含量与分布特征。参照国家土壤环境质量标准(GB15618-1995)中的二级标准,采用单项污染指数法和综合污染指数法,对其重金属污染现状进行评价。结果表明：232份土壤样品中,Cd、Hg、As、Cr的超标率分别为45.06%、7.73%、5.15%和1.29%,未见Pb超标;37.34%的土壤受到不同程度的污染,Cd污染情况最为严重,Hg污染次之;土壤污染以单一重金属污染为主,未出现3种及以上重金属复合污染。各地污染状况呈现区域差异,东莞地区受污染的样品比例较大,珠海和广州的污染情况相对较轻。该区域的土壤重金属污染形势不容乐观,其可能给农业生产带来的风险应引起重视。     

Cryptic Metabolites from Marine-Derived Microorganisms Using OSMAC and Epigenetic Approaches

Marine microorganisms have proven to be a source of new natural products with a wide spectrum of biological activities relevant in different industrial sectors. The ever-increasing number of sequenced microbial genomes has highlighted a discrepancy between the number of gene clusters potentially encoding the production of natural products and the actual number of chemically characterized metabolites for a given microorganism. Homologous and heterologous expression of these biosynthetic genes, which are often silent under experimental laboratory culture conditions, may lead to the discovery of new cryptic natural products of medical and biotechnological interest. Several new genetic and cultivation-based strategies have been developed to meet this challenge. The OSMAC approach (one strain—many compounds), based on modification of growth conditions, has proven to be a powerful strategy for the discovery of new cryptic natural products. As a direct extension of this approach, the addition of chemical elicitors or epigenetic modifiers have also been used to activate silent genes. This review looks at the structures and biological activities of new cryptic metabolites from marine-derived microorganisms obtained using the OSMAC approach, the addition of chemical elicitors, and enzymatic inhibitors and epigenetic modifiers. It covers works published up to June 2021.