In order to save energy consumption for the downstream processes, consecutive very-high-gravity b... more In order to save energy consumption for the downstream processes, consecutive very-high-gravity batch fermentation was developed for ethanol production with the self-flocculating yeast Saccharomyces cerevisiae flo. The fermentation system exhibited a high ethanol productivity of 8.2 g/(L x h) with average ethanol concentration around 120 g/L. However, deterioration of the sedimentation performance of yeast flocs was observed as the consecutive fermentation process was prolonged, which significantly extended the time required for yeast flocs to separate from fermentation broth, and exaggerated the inhibition of high ethanol concentration on the yeast flocs, making them quickly lost viability and the fermentation system interrupted after 11 consecutive batches. Experimental results illustrated that decrease of the size of yeast flocs was the main reason, which could be prevented by stimulating the propagation of the yeast flocs. Thus, yeast was purged from the fermentation system at the end of each batch, and the concentration of yeast flocs within the fermentor was maintained at a relatively low level to stimulate their propagation. Although the ethanol productivity was decreased to 4.0 g/(L x h), the size of yeast flocs was stabilized after 10 consecutive batches and maintained for another 14 batches without further decrease, indicating the fermentation system could be operated reliably.
“Molecular farming” in plants with significant advantages in cost and safety is touted as a promi... more “Molecular farming” in plants with significant advantages in cost and safety is touted as a promising platform for the production of complex pharmaceutical proteins. While whole-plant produced biopharmaceuticals account for a significant portion of the preclinical and clinical pipeline, plant cell suspension culture, which integrates the merits of whole-plant systems with those of microbial fermentation, is emerging as a more compliant alternative “factory”. However, low protein productivity remains a major obstacle that limits extensive commercialization of plant cell bioproduction platform. This review highlights the advantages and recent progress in plant cell culture technology and outlines viable strategies at both the biological and process engineering levels for advancing the economic feasibility of plant cell-based protein production. Approaches to overcome and solve the associated challenges of this culture system that include non-mammalian glycosylation and genetic instability will also be discussed.
The global population is expected to increase by approximately 3 billion people by 2050. With thi... more The global population is expected to increase by approximately 3 billion people by 2050. With this increase in population, industry, transportation the cost of fossil fuels will grow dramatically. New technologies are needed for fuel extraction using feedstocks that do not threaten food security, cause minimal or no loss of natural habitat and soil carbon. At the same time, waste management has to be improved and environmental pollution should be minimized or eliminated. Liquid biofuels such as lignocellulosic-based ethanol from plant biomass and algal-based biodiesel are sustainable, alternative biofuels that could stabilize national security and provide clean energy for future generations. Ideally, the technology should also foster recycling of agricultural feedstocks and improve soil fertility and human health. This article provides updated information on the energy potential and breadth of liquid biofuel biotechnology.
In order to save energy consumption for the downstream processes, consecutive very-high-gravity b... more In order to save energy consumption for the downstream processes, consecutive very-high-gravity batch fermentation was developed for ethanol production with the self-flocculating yeast Saccharomyces cerevisiae flo. The fermentation system exhibited a high ethanol productivity of 8.2 g/(L x h) with average ethanol concentration around 120 g/L. However, deterioration of the sedimentation performance of yeast flocs was observed as the consecutive fermentation process was prolonged, which significantly extended the time required for yeast flocs to separate from fermentation broth, and exaggerated the inhibition of high ethanol concentration on the yeast flocs, making them quickly lost viability and the fermentation system interrupted after 11 consecutive batches. Experimental results illustrated that decrease of the size of yeast flocs was the main reason, which could be prevented by stimulating the propagation of the yeast flocs. Thus, yeast was purged from the fermentation system at the end of each batch, and the concentration of yeast flocs within the fermentor was maintained at a relatively low level to stimulate their propagation. Although the ethanol productivity was decreased to 4.0 g/(L x h), the size of yeast flocs was stabilized after 10 consecutive batches and maintained for another 14 batches without further decrease, indicating the fermentation system could be operated reliably.
“Molecular farming” in plants with significant advantages in cost and safety is touted as a promi... more “Molecular farming” in plants with significant advantages in cost and safety is touted as a promising platform for the production of complex pharmaceutical proteins. While whole-plant produced biopharmaceuticals account for a significant portion of the preclinical and clinical pipeline, plant cell suspension culture, which integrates the merits of whole-plant systems with those of microbial fermentation, is emerging as a more compliant alternative “factory”. However, low protein productivity remains a major obstacle that limits extensive commercialization of plant cell bioproduction platform. This review highlights the advantages and recent progress in plant cell culture technology and outlines viable strategies at both the biological and process engineering levels for advancing the economic feasibility of plant cell-based protein production. Approaches to overcome and solve the associated challenges of this culture system that include non-mammalian glycosylation and genetic instability will also be discussed.
The global population is expected to increase by approximately 3 billion people by 2050. With thi... more The global population is expected to increase by approximately 3 billion people by 2050. With this increase in population, industry, transportation the cost of fossil fuels will grow dramatically. New technologies are needed for fuel extraction using feedstocks that do not threaten food security, cause minimal or no loss of natural habitat and soil carbon. At the same time, waste management has to be improved and environmental pollution should be minimized or eliminated. Liquid biofuels such as lignocellulosic-based ethanol from plant biomass and algal-based biodiesel are sustainable, alternative biofuels that could stabilize national security and provide clean energy for future generations. Ideally, the technology should also foster recycling of agricultural feedstocks and improve soil fertility and human health. This article provides updated information on the energy potential and breadth of liquid biofuel biotechnology.
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