Bioprocess

About: Bioprocess is a research topic. Over the lifetime, 2219 publications have been published within this topic receiving 50972 citations.

Effects and applications of sub-lethal ultrasound, electroporation and UV radiations in bioprocessing

Abstract: Advances in bioprocess technology involving microbial cells have led to increased and improved production of beneficial new products and bioactive compounds. However, the semipermeable barrier of the cell membrane often retards the efficient productivity or reaction rate of the cells. Physical treatments such as ultrasound, electroporation and UV radiation provide an efficient approach to increase membrane permeability, leading to enhanced productivity of microbial cells. It is important to note that extensive membrane permeabilization by these physical treatments could be detrimental to cell viability leading to lower yield. An appropriate selection of sublethal dosage and intensity of these physical treatments are critical to preserve the viability of cells and at the same time maintain their bioprocess applications. Despite the promising applications of these physical treatments, safety issues related to possible genotoxicity or mutation of cells upon treatments have been raised. This genotoxic effect of physical treatments could be prevented if appropriate measures are taken, without compromising their bioprocess potentials. The current review highlights the effect of sublethal physical treatments such as ultrasound, electroporation and UV radiation on the viability of cells, their potential bioprocess applications, and the possibility of mutations.

Antibody production in Bacillus megaterium: Strategies and physiological implications of scaling from microtiter plates to industrial bioreactors

Abstract: Bacillus megaterium was used as an alternative high potential microbial production system for the production of antibody fragment D1.3 scFv. The aim of the study was to follow a holistic optimization approach from medium screening in small scale microtiter platforms, gaining deeper process understanding in the bioreactor scale and implementing advanced process strategies at larger scales (5–100 L). Screening and optimization procedures were supported by statistical design of experiments and a genetic algorithm approach. The process control relied on a soft-sensor for biomass estimation to establish a μ-oscillating time-dependent fed-batch strategy. Several cycles of growth phases and production phases, equal to starving phases, were performed in one production. Flow cytometry was used to monitor and characterize the dynamics of secretion and cell viability. Besides the biosynthesis of the product, secretion was optimized by an appropriate medium design considering different carbon sources, metal ions, (NH 4 ) 2 SO 4 , and inductor concentrations. For bioprocess design, an adapted oscillating fed-batch strategy was conceived and successfully implemented at an industrially relevant scale of 100 L. In comparison to common methods for controlling fed-batch profiles, the developed process delivered increased overall productivities. Thereby measured process parameters such as growth stagnation or productivity fluctuations were directly linked to single cell or population behavior leading to a more detailed process understanding. Above all, the importance of single cell analysis as key scale-free tool to characterize and optimize recombinant protein production is highlighted, since this can be applied to all development stages independently of the cultivation platform.

Optimization of biomass production of a mutant of Yarrowia lipolytica with an increased lipase activity using raw glycerol

Abstract: The yeast Yarrowia lipolytica accumulates oils and is able to produce extracellular lipases when growing in different carbon sources including glycerol, the principal by-product of the biodiesel industry. In this study, biomass production of a novel mutant strain of Y. lipolytica was statistically optimized by Response Surface Methodology in media containing biodiesel-derived glycerol as main carbon source. This strain exhibited distinctive morphological and fatty acid profile characteristics, and showed an increased extracellular lipase activity. An organic source of nitrogen and the addition of 1.0 g/l olive oil were necessary for significant lipase production. Plackett-Burman and Central Composite Statistical Designs were employed for screening and optimization of fermentation in shaken flasks cultures, and the maximum values obtained were 16.1 g/l for biomass and 12.2 Units/ml for lipase, respectively. Optimized batch bioprocess was thereafter scaled in aerated bioreactors and the values reached for lipase specific activity after 95 % of the glycerol had been consumed, were three-fold higher than those obtained in shaken flasks cultures. A sustainable bioprocess to obtain biomass and extracellular lipase activity was attained by maximizing the use of the by-products of biodiesel industry.