Showing papers on "Bioprocess published in 1988"

Recirculating bioreactor–separator system for simultaneous biotransformation and recovery of product: Immobilized L-aspartate β-decarboxylase reactor system

Abstract: A new combined bioreactor-separator system was designed and its operational feasibility demonstrated in order to develop a bioprocess that enables us to handle simultaneous biotransformation and recovery of product by crystallization. Enzymatic conversion of L-aspartate to L-alanine by L-aspartate β-decarboxylase from Pseudomonas dacunhae (ATCC 21192) was used as a model system for this study to demonstrate the principles involved in the bioprocess design. Immobilized cells of P. dacunhae containing the enzyme were fluidized in a tapered column type of bioreactor and a filter-crystallizer combination was used as a separator unit in our experimental system. It was found that almost a theoretical yield was achieved, and the process control for both the bioreactor operation and separation was relatively easy. The Production systems, namely, the recirculating bioreactor separator combination system and the conventional batch reactor system, were analyzed and compared based on the results obtained form this study, and it was found that a significant cost reduction, by about 20%, can be achieved when the recirculating bioreactor–separator combination system was employed. Based on these findings, it is anticipated that the conceptual design of the bioreactor–separator combination system evaluated in this study has some potential for industrial application.

Objectives of coal bioprocessing and approaches

Abstract: Studies in coal bioprocessing are just getting underway and still in its infancy. Conceptually coal bioprocessing can be categorized into two areas: (1) coal cleaning-removal of undesirable components such as sulfur, nitrogen, trace metals; and (2) coal conversion - microbial liquefaction, microbial gasification, microbial pretreatment, methane production. The ability of any microbe or microbial consortia to break down a complex structure depends on the types of chemical bonds and the three dimensional environment around the bonds. Therefore, intertwined with coal bioprocessing is an understanding of the coal macromolecular structure and biochemical mechanisms by which microbes/enzymes break bonds. This paper discusses microbial coal transformation in aerobic systems, enzymes versus whole cells, anaerobic bioconversion of coal, microbial coal cleaning, and bioprocess engineering.

Integrated downstream processing with membranes

Abstract: The cost of the selected downstream process usually determines the economic feasibility of the bioprocess. Generally, 4 steps can be identified : 1. removal of the product from the fermentation broth 2. concentration of the product, which mainly means the removal of water 3. product purification or the removal of impurities 4. product conditioning This paper will concentrate on the first and second steps which are suitable for membrane processes. Depending on the nature of the feedstock and the product, the first stage has to be split up into three steps : cell concentration, disintegration and separation.

The Principles of Bioprocess Technology

Abstract: Chapter 1 mentioned the central importance of the catalyst in biotechnological processes. A culture suitable for production purposes—that is, a cell culture with sufficiently high population density and capacity for economic production of the product—must be available.