An integrated algal sulphate reducing high rate ponding process for the treatment of acid mine drainage wastewaters

Acid mine drainage pollution may be associated with large water volume flows and exceptionally long periods of time over which the drainage may require treatment. While the use and role of sulphate reducing bacteria has been demonstrated in active treatment systems for acid mine drainage remediation, reactor size requirement and the cost and availability of the carbon and electron donor source are factors which constrain process development. Little attention has focussed on the use of waste stabilisation ponding processes for acid mine drainage treatment. Wastewater ponding is a mature technology for the treatment of large water volumes and its use as a basis for appropriate reactor design for acid mine drainage treatment is described including high rates of sulphate reduction and the precipitation of metal sulphides. Together with the co-disposal of organic wastes, algal biomass is generated as an independent carbon source for SRB production. Treatment of tannery effluent in a custom-designed high rate algal ponding process, and its use as a carbon source in the generation and precipitation of metal sulphides, has been demonstrated through piloting to the implementation of a full-scale process.The treatment of both mine drainage and zinc refinery wastewaters are reported. A complementary role for microalgal production in the generation of alkalinity and bioadsorptive removal of metals has been utilised and an Integrated 'Algal Sulphate Reducing Ponding Process for the Treatment of Acidic and Metal Wastewaters' (ASPAM) has been described.     

Recombinant protein production and streptomycetes

The biopharmaceutical market has come a long way since 1982, when the first biopharmaceutical product, recombinant human insulin, was launched. Just over 200 biopharma products have already gained approval. The global market for biopharmaceuticals which is currently valued at over US$99 billion has been growing at an impressive compound annual growth rate over the previous years. To produce these biopharmaceuticals and other industrially important heterologous proteins, different prokaryotic and eukaryotic expression systems are used. All expression systems have some advantages as well as some disadvantages that should be considered in selecting which one to use. Choosing the best one requires evaluating the options--from yield to glycosylation, to proper folding, to economics of scale-up. No host cell from which all the proteins can be universally expressed in large quantities has been found so far. Therefore, it is important to provide a variety of host-vector expression systems in order to increase the opportunities to screen for the most suitable expression conditions or host cell. In this overview, we focus on Streptomyces lividans, a Gram-positive bacterium with a proven excellence in secretion capacity, as host for heterologous protein production. We will discuss its advantages and disadvantages, and how with systems biology approaches strains can be developed to better producing cell factories.     

THE USE OF SEAWEEDS IN INTEGRATED AQUACULTURE: THE CHILEAN EXPERIENCE

Buschmann, A. H. Departamento de Acuicultura, Universidad de Los Lagos, Casilla 933, Osorno, Chile.abuschma@ulagos.cl In Chile, salmon cultivation is well established, and produces over 200,000 tons yr-1. Integrated aquaculture has been proposed as an environmentally friendly way of recycling the waste of intensive aquaculture practices. An initial approach has been considered which contemplates the use of culture lines surrounding fish cages. Several studies have demonstrated under these conditions seaweeds can maintain higher production levels and present higher nitrogen contents as compared to cultures without the presence of fish cages. However, success has not been total, partly because the amount of seaweeds required to remove a significant proportion of the waste produced from intensive large-scale cultivation systems is very large. In this context, the use of a multi-layered seaweed cultivation of Gracilaria and Macrocystis is suggested. On the other hand, land-based systems have been proposed as a technological alternative for integrated aquaculture. The latter type of systems are technically feasible, although, the high level of investment required at present. Our results indicate that Gracilaria is capable of removing a significant proportion of the ammonium excreted by fish. These studies indicate that annual fish production can reach over 30 kg.m-3, with an associated Gracilaria production of 49 kg (wet). m-2. y-1. Finally, the environmental benefits associated with the development of integrated tank cultivation were assessed indicating that by integrating seaweed cultivation into a fish farm, the economic profitability of a commercial fish operation is not affected when internalizing the environmental costs which could be incurred for environmental compliance. (Grant: FONDEF D991/1101)     

Cell-free translation systems for protein engineering

Cell-free translation systems have developed significantly over the last two decades and improvements in yield have resulted in their use for protein production in the laboratory. These systems have protein engineering applications, such as the production of proteins containing unnatural amino acids and development of proteins exhibiting novel functions. Recently, it has been suggested that cell-free translation systems might be used as the fundamental basis for cell-like systems. We review recent progress in the field of cell-free translation systems and describe their use as tools for protein production and engineering.     

Gene therapy using retroviral vectors

Gene therapy is a novel approach for treating various congenital and acquired genetic disorders, including cancer, heart disease, and acquired immune deficiency syndrome. Amongst possible gene delivery systems, retroviral vector mediated gene transfer has been the most extensively studied and has been approved for use in over 40 current Phase I/II clinical trials for the treatment of various disorders, primarily cancers. Recent technological improvements include the optimization of vector production by concentration and lyophilization, resulting in high titers of vectors, as well as the large-scale production of vector-produced cells for the treatment of brain cancer. Present clinical protocols require specialized care centers with expertise in molecular biology and cell transplantation. Considerable effort is under way to develop retroviral vectors that can be both injected directly into the body and targeted to specific cell types within the body. Such vectors could be administered to patients by physicians in their offices. Successful development of this new technology would greatly expand the clinical potential of gene therapy.     

Metabolic engineering based on systems biology for chemicals production

Microorganisms have been the main sources for the production of chemicals. Production of chemicals requires the development of low-cost and higher-yield processes. Towards this goal, microbial strains with higher levels of production should be first considered. Metabolic engineering has been used extensively over the past two to three decades to increase production of these chemicals. Advances in omics technology and computational simulation are allowing us to perform metabolic engineering at the systems level. By combining the results of omics analyses and computational simulation, systems biology allows us to understand cellular physiology and characteristics, which can subsequently be used for designing strategies. Here, we review the current status of metabolic engineering based on systems biology for chemical production and discuss future prospects.     

Metabolic engineering based on systems biology for chemicals production

Microorganisms have been the main sources for the production of chemicals. Production of chemicals requires the development of low-cost and higher-yield processes. Towards this goal, microbial strains with higher levels of production should be first considered. Metabolic engineering has been used extensively over the past two to three decades to increase production of these chemicals. Advances in omics technology and computational simulation are allowing us to perform metabolic engineering at the systems level. By combining the results of omics analyses and computational simulation, systems biology allows us to understand cellular physiology and characteristics, which can subsequently be used for designing strategies. Here, we review the current status of metabolic engineering based on systems biology for chemical production and discuss future prospects.     

Synthetic biology advancing clinical applications

The 'omics' era, with its identification of genetic and protein components, has combined with systems biology, which provided insights into network structures, to set the stage for synthetic biology, an emerging interdisciplinary life science that uses engineering principles. By capitalizing on an iterative design cycle that involves molecular and computational biology tools to assemble functional designer devices from a comprehensive catalogue of standardized biological components with predictable functions, synthetic biology has significantly advanced our understanding of complex control dynamics that program living systems. Such insights, collected over the past decade, are priming a variety of synthetic biology-inspired biomedical applications that have the potential to revolutionize drug discovery and production technologies, as well as treatment strategies for infectious diseases and metabolic disorders.     

Non-conventional yeasts as hosts for heterologous protein production.

Yeasts are an attractive group of lower eukaryotic microorganisms, some of which are used in several industrial processes that include brewing, baking and the production of a variety of biochemical compounds. More recently, yeasts have been developed as host organisms for the production of foreign (heterologous) proteins. Saccharomyces cerevisiae has usually been the yeast of choice, but an increasing number of alternative non-Saccharomyces yeasts has now become accessible for modern molecular genetics techniques. Some of them exhibit certain favourable traits such as high-level secretion or very strong and tightly regulated promoters, offering significant advantages over traditional bakers' yeast. In the present work, the current status of Kluyveromyces lactis, Yarrowia lipolytica, Hansenula polymorpha and Pichia pastoris (the best-known alternative yeast systems) is reviewed. The advantages and limitations of these systems are discussed in relation to S. cerevisiae.     

Potential of plants to produce recombinant protein products

Plants have great potential as photosynthetic factories to produce pharmaceutically important and commercially valuable biomedicines and industrial proteins at low cost. The U.S. Food and Drug Administration (U.S. FDA) has approved the drug Elelyso (taliglucerase alfa) produced by carrot cells for treatment of type 1 Gaucher’s disease in 2012. The commercial potential of biomedicines produced by molecular farming has dramatically improved due to the success of an experimental drug called ZMapp, which has immunological activity in Ebola patients. A cocktail of three monoclonal antibodies was produced in tobacco (Nicotiana benthamiana) plants (Chen and Davis 2016). At present, very few drugs made by this technology have been approved by worldwide authorities such as the U.S. FDA. However, plants have been proposed as a novel paradigm for commercial production of proteins over the next decade. In recent years, leading researchers on molecular farming have given more priority to the area of animal-free therapeutic proteins such as parenteral and oral vaccines. Although plant-based platforms have considerable advantages over traditional systems such as bacterial and animal systems, there are several obstacles to commercial-scale production, especially with regards to improving the quality and quantity of plant-produced biologics and industrial materials. One of the biggest barriers to commercialization of this technology is the intense scrutiny of these new plant varieties by regulatory agencies and the public as well as the high costs associated with their regulatory approval.     

Challenges in therapeutic glycoprotein production

Protein-based drugs constitute about a quarter of new approvals with a majority being glycoproteins. Increasing use of glycoproteins, such as monoclonal antibodies, at high therapeutic doses is challenging current production capacity. Mammalian cell culture, which is currently the production system of choice for glycoproteins, has several disadvantages including high cost of goods, long cycle times and, importantly, limited control over glycosylation. In view of this, several expression systems are currently being explored as alternatives to mammalian cell culture, these include yeast, plant and insect expression systems. Each of these has different merits for the production of therapeutic glycoproteins and can lead to enhanced therapeutic efficiency.     

Development of buffalo gourd (Cucurbita foetidissima) as a semiaridland starch and oil crop

Cucurbita foetidissima (buffalo gourd), a semiaridland plant native to the Greater Southwest, has been utilized by humans for thousands of years, primarily as food and medicine. In recent years, buffalo gourd has been the focus of an important domestication program at the University of Arizona. This research has led to 2 main cultural systems, an annual mode for root-starch production, and a perennial mode primarily for seed-oil production. In our paper, over 75 references are analyzed to evaluate the potential of buffalo gourd as an energy, chemical-products, and food crop. Priorities are suggested, including investigation of buffalo gourd as a novel crop for New Mexico's developing fuel ethanol industry.     

无细胞蛋白表达体系研究进展及在生物制药领域中的应用

作为一种快速高效的体外蛋白合成手段,无细胞蛋白表达体系(Cell-free Protein Synthesis,CFPS)一直以来就被广泛应用于基础生物学领域的研究。与传统的基于细胞的体内表达体系相比,CFPS突破了细胞的生理限制,其可调控性强、对毒性蛋白的耐受力高,使得许多很难在体内合成的复杂蛋白在体外顺利表达。近年来随着研究人员不断对CFPS进行优化,通过简化制备工艺、开发价格低廉的能量再生系统、稳定底物供应、促进蛋白正确折叠等方式,成功研发出生产效率高、成本低廉、反应体积大的表达体系。凭借其高通量和大规模的蛋白表达优势,CFPS为解决生物制药领域中面临的难题提供了新的解决思路,并成功地应用于高通量药物筛选、大规模生产重组蛋白药物、个体化定制肿瘤疫苗等领域,显示出其在生物制药领域的重要应用潜力。     

Origins of food crops connect countries worldwide

Research into the origins of food plants has led to the recognition that specific geographical regions around the world have been of particular importance to the development of agricultural crops. Yet the relative contributions of these different regions in the context of current food systems have not been quantified. Here we determine the origins (‘primary regions of diversity’) of the crops comprising the food supplies and agricultural production of countries worldwide. We estimate the degree to which countries use crops from regions of diversity other than their own (‘foreign crops’), and quantify changes in this usage over the past 50 years. Countries are highly interconnected with regard to primary regions of diversity of the crops they cultivate and/or consume. Foreign crops are extensively used in food supplies (68.7% of national food supplies as a global mean are derived from foreign crops) and production systems (69.3% of crops grown are foreign). Foreign crop usage has increased significantly over the past 50 years, including in countries with high indigenous crop diversity. The results provide a novel perspective on the ongoing globalization of food systems worldwide, and bolster evidence for the importance of international collaboration on genetic resource conservation and exchange.     

Prospects for molecular farming in the green alga Chlamydomonas

Protein-based therapeutics have enjoyed great success over the past decade. Unfortunately, this clinical success has come with a heavy price tag that is due to the inherently high costs of the capitalization and production of these complex molecules using current mammalian-based fermentation systems. Recent progress has been made in the production of recombinant proteins, including antibodies, in the eukaryotic unicellular green alga Chlamydomonas reinhardtii. C. reinhardtii offers an attractive alternative to traditional mammalian-based expression systems for several reasons, including its ability to provide stable plastid and nuclear transformants rapidly and its inherently low costs for capitalization and production.     

Collection and production of native seeds for ecological restoration

The global push to achieve ecosystem restoration targets has resulted in an increased demand for native seeds that current production systems are not able to fulfill. In many countries, seeds used in ecological restoration are often sourced from natural populations. Though providing seed that is reflective of the genetic diversity of a species, wild harvesting often cannot meet the demands for large‐scale restoration and may also result in depletion of native seed resources through over harvesting. To improve seed production and decrease seed costs, seed production systems have been established in several countries to generate native seeds based on agricultural or horticultural production methods or by managing natural populations. However, there is a need to expand these production systems which have a primary focus on herbaceous species to also include slower maturing shrub and tree seed. Here we propose that to reduce the threat of overharvest on the viability of natural populations, seed collection from natural populations should be replaced or supplemented by seed production systems. This overview of seed production systems demonstrates how to maximize production and minimize unintended selection bias so that native seed batches maintain genetic diversity and adaptability to underpin the success of ecological restoration programs.     

Mini-review: high rate algal ponds,flexible systems for sustainable wastewater treatment

Over the last 20 years, there has been a growing requirement by governments around the world for organisations to adopt more sustainable practices. Wastewater treatment is no exception, with many currently used systems requiring large capital investment, land area and power consumption. High rate algal ponds offer a sustainable, efficient and lower cost option to the systems currently in use. They are shallow, mixed lagoon based systems, which aim to maximise wastewater treatment by creating optimal conditions for algal growth and oxygen production—the key processes which remove nitrogen and organic waste in HRAP systems. This design means they can treat wastewater to an acceptable quality within a fifth of time of other lagoon systems while using 50% less surface area. This smaller land requirement decreases both the construction costs and evaporative water losses, making larger volumes of treated water available for beneficial reuse. They are ideal for rural, peri-urban and remote communities as they require minimum power and little on-site management. This review will address the history of and current trends in high rate algal pond development and application; a comparison of their performance with other systems when treating various wastewaters; and discuss their potential for production of added-value products. Finally, the review will consider areas requiring further research.     

Plant cell cultures for the production of recombinant proteins

The use of whole plants for the synthesis of recombinant proteins has received a great deal of attention recently because of advantages in economy, scalability and safety compared with traditional microbial and mammalian production systems. However, production systems that use whole plants lack several of the intrinsic benefits of cultured cells, including the precise control over growth conditions, batch-to-batch product consistency, a high level of containment and the ability to produce recombinant proteins in compliance with good manufacturing practice. Plant cell cultures combine the merits of whole-plant systems with those of microbial and animal cell cultures, and already have an established track record for the production of valuable therapeutic secondary metabolites. Although no recombinant proteins have yet been produced commercially using plant cell cultures, there have been many proof-of-principle studies and several companies are investigating the commercial feasibility of such production systems.     

Chloroplast-derived vaccines against human diseases: achievements, challenges and scopes

Infectious diseases represent a continuously growing menace that has severe impact on health of the people worldwide, particularly in the developing countries. Therefore, novel prevention and treatment strategies are urgently needed to reduce the rate of these diseases in humans. For this reason, different options can be considered for the production of affordable vaccines. Plants have been proved as an alternative expression system for various compounds of biological importance. Particularly, plastid genetic engineering can be potentially used as a tool for cost-effective vaccine production. Antigenic proteins from different viruses and bacteria have been expressed in plastids. Initial immunological studies of chloroplast-derived vaccines have yielded promising results in animal models. However, because of certain limitations, these vaccines face many challenges on production and application level. Adaptations to the novel approaches are needed, which comprise codon usage and choice of proven expression cassettes for the optimal yield of expressed proteins, use of inducible systems, marker gene removal, selection of specific antigens with high immunogenicity and development of tissue culture systems for edible crops to prove the concept of low-cost edible vaccines. As various aspects of plant-based vaccines have been discussed in recent reviews, here we will focus on certain aspects of chloroplast transformation related to vaccine production against human diseases.     

Parasitic helminths of the pig: factors influencing transmission and infection levels.

The occurrence of parasitic helminth species as well as infection intensities are markedly influenced by the type of swine production system used. The present review focusses mainly on the situation in temperate climate regions. Generally, over the past decades there has been a decrease in the number of worm species and worm loads in domestic pigs due to a gradual change from traditional to modern, intensive production systems. The reasons for some species being apparently more influenced by management changes than others are differences in the basic biological requirements of the pre-infective developmental stages, together with differences in transmission characteristics and immunogenicity of the different worm species. Control methods relevant for the different production systems are discussed. Outdoor rearing and organic pig production may in the future be confronted with serious problems because of particularly favourable conditions for helminth transmission. In addition, in organic farms preventive usage of anthelmintics is not permitted.