Production methods for viral particles

Viral particles and virus-like particles (VLPs) or capsids are becoming important vehicles and templates in bio-imaging, drug delivery and materials sciences. Viral particles are prepared by infecting the host organism but VLPs are obtained from cells that express a capsid protein. Some VLPs are disassembled and then re-assembled to incorporate a material of interest. Cell-free systems, which are amenable to manipulating the viral assembly process, are also available for producing viral particles. Regardless of the production system employed, the particles are functionalized by genetic and/or chemical engineering. Here, we review various methods for producing and functionalizing viral particles and VLPs, and we discuss the merits of each system.     

Garbage Composting for Mushroom Production

Laboratory and pilot-plant composting of garbage mixtures of newspaper and vegetable waste has demonstrated that garbage can be converted to a medium that produces mushrooms (Agaricus campestris) in good yield. Sewage sludge was less satisfactory than newspaper, gumwood sawdust, or vegetable waste as a compost material for growing mushrooms. A sample of commercially produced compost was found to yield mushrooms in the same quantity as was produced in the laboratory experiments.     

Production methods for rabies vaccine

A concise history of rabies vaccine production methods, including worldwide production methods in animals and cell culture are presented. Received 22 January 1996/ Accepted in revised form 03 February 1997     

Wastewater Equalization for Batch Production Plants

This paper proposes a systematic approach for debottlenecking wastewater treatment systems of batch production plants in which wastewater generation rates fluctuate at different production stages. In batch production plants, buffer tanks are commonly used to regulate the wastewater feed rate, concentration, temperature, etc., before the wastewater is sent to treatment units. The size of the buffer tank needs to be designed properly so that its size is minimized and still has enough capacity to handle various operating conditions. In many cases, the size of the buffer tank can be reduced or eliminated by simply adjusting the batch production schedules. This paper proposes a graphical method that systematically finds the appropriate size buffer tank based upon historical data, assuming that production schedule changes are not allowed. For systems that allow production schedules to be changed, a mathematical model is used to optimize the size of the buffer tank.     

High-Throughput Functional Genomics for Energy Production

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Microbial Consortia for Hydrogen Production Enhancement

Ten efficient hydrogen-producing strains affiliated to the Clostridium genus were used to develop consortia for hydrogen production. In order to determine their saccharolytic and proteolytic activities, glucose and meat extract were tested as fermentation substrates, and the best hydrogen-producing strains were selected. The C. roseum H5 (glucose-consuming) and C. butyricum R4 (protein-degrading) co-culture was the best hydrogen-producing co-culture. The end-fermentation products for the axenic cultures and co-cultures were analyzed. In all cases, organic acids, mainly butyrate and acetate, were produced lowering the pH and thus inhibiting further hydrogen production. In order to replace the need for reducing agents for the anaerobic growth of clostridia, a microbial consortium including Clostridium spp. and an oxygen-consuming microorganism able to form dense granules (Streptomyces sp.) was created. Increased yields of hydrogen were achieved. The effect of adding a butyrate-degrading bacteria and an acetate-consuming archaea to the consortia was also studied.     

关于生物制氢

简述了生物制氢发展过程及现今取得的成果。经济发展和人类对能源需求造成了诸如环境污染、常规能源短缺等一系列问题。因此 ,作为一种新型、可再生能源 ,氢能研究已经受到了人们高度重视。与其它制氢方法相比 ,生物制氢有着突出的优点 ,尤其是藻类利用太阳能光解水制氢 ,使人们看到了解决能源问题的希望。     

Production of Antiserum for Staphylococcal Enterotoxin

Immunization of rabbits with approximately 95% pure enterotoxin B and approximately 20 and 50% pure enterotoxin A yielded specific antisera which required no and little absorption, respectively, when used in the slide double-diffusion test. Methods for purifying enterotoxin A and for the production and absorption of antisera are presented.     

A Bioreactor-Crystallizer for L-Malic Acid Production

A bioreactor with associated crystallizer for the accumulation of a highly concentrated slurry product has been developed and investigated. The transformation of Ca-fumarate to Ca-L-malate by the action of the fumarase of immobilized Brevibacterium flavum cells focussed on the performance of this newly-devised bioreactor-crystallizer system.

The following results were obtained

(1) The fumarase reaction in the bioreactor proceeded at a rate that was first-order in apparent substrate concentration.

(2) The reaction rate increased with the addition of Na₂-fumarate to the substrate solution.

(3) The reaction rate was independent of the substrate circulation rate and the initial substrate concentration in the crystallizer.

(4) Fumarase activity of immobilized B. flavum cells was stable after 10 repeated uses over a period of 10 days.

(5) Maximum concentration of the product, final conversion ratio of the substrate and the productivity of the bioreactor-crystallizer system were much higher than those for a conventional bioreactor using solubilized Ca-fumarate as a substrate.     

Microplate Assay for Colletotrichum Spore Production

A simple microplate method was devised to assay spore production by Colletotrichum gloeosporioides by growing the fungus on 1 ml of solid media in the wells of tissue culture plates. Growth and sporulation on microplates were compared at days 4 and 8 with growth and sporulation in 100-ml liquid batch cultures that involved 11 common media. Spore production per unit volume of medium was the same for solid and liquid forms of the media. Qualitative assessment of mycelial growth measured on microplates agreed with that of growth measured in liquid cultures. The microplate assay indicated that V8 juice was the best medium and that an organic content of about 6 mg/ml was optimal for high sporulation and low mycelium production. The assay provides a convenient, rapid, and inexpensive means of screening media for the production of fungal conidia in large numbers, to be used, for example, in biological control programs.     

Availability Analysis for Multitask Production Systems

A multitask production system is one in which different subsets of the components can be used to perform distinct functions or tasks. For such a system, some of the components are used intermittently and some may be used continuously. This type of operational protocol is often applied to flexible manufacturing systems. In this paper, we develop models of the operational reliability and of the availability of multitask systems. We construct models for both the case in which preventive maintenance is used and the case in which preventive maintenance is not used. The models presented here constitute an extension to existing models to allow the study of the behavior of modern manufacturing equipment.     

New Method for Detecting Bacteriocin Production

Bacteriocin production can be easily detected by using both sides of the agar contained in a standard petri dish.     

Solid-Substrate Fermentor for Ochratoxin A Production

A laboratory-scale fermentor designed for solid-substrate fermentation was constructed and tested. Its capacity to produce ochratoxin under varied conditions was determined with wheat as substrate. Ochratoxin yields of 2,000 to 2,500 μg/g of wheat were regularly obtained, and occasionally yields as high as 4,000 μg/g were obtained. The most critical factor in the fermentation was initial substrate moisture content; wheat tempered at 30 to 31% moisture produced the highest yields. Other variables tested were agitation and aeration rates, initial static culture time, and inoculum types and volumes.     

Continuous Processing for Production of Biopharmaceuticals

The merits of continuous processing over batch processing are well known in the manufacturing industry. Continuous operation results in shorter process times due to omission of hold steps, higher productivity due to reduced shutdown costs, and lowers labor requirement. Over the past decade, there has been an increasing interest in continuous processing within the bioprocessing community, specifically those involved in production of biotherapeutics. Continuous operations in upstream processing (perfusion) have been performed for decades. However, recent development of continuous downstream operations has led the industry to envisage an integrated bioprocessing platform for efficient production. The regulators, key players in the biotherapeutic industry, have also expressed their interest and willingness in this migration from the traditional batch processing. This paper aims to review major developments in continuous bioprocessing in the past decade. A discussion of pros and cons of the different proposed approaches has also been presented.