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Biodiesel, Power Alcohol and Butanol Production
Published in Debabrata Das, Soumya Pandit, Industrial Biotechnology, 2021
The concentration of undissociated butyric acid triggers cells to enter the solventogenic phase. In the solventogenesis phase, acids are re-assimilated into acetone, butanol and ethanol. A semi-continuous approach is generally used for the industrial production of butanol using fermentation. Each fermentation steps lasts for a period of about 21 d (Jang and Lee, 2015). The fermentation plants typically have several trains of big tanks (up to 400 m3). Fermentation is carried out using a fed-batch method. Fresh feedstock, together with periodic additions of seed culture, flows through the fermenters. This provides sufficient residence time for re-assimilation of the acids produced in the acidogenesis phase to solvents in solventogenesis. Acetone, butanol and ethanol are produced by fermentation in a proportion of 3:6:1 by mass. The final product can then be recovered by distillation based on the boiling points of acetone, ethanol and butanol which are 56 °C, 78 °C and 118 °C, respectively. A new approach of biobutanol production involves the use of metabolically engineered Clostridia. The metabolically engineered Clostridia immediately enter the solvent-organic phase, avoiding the acidogenic phase. The use of metabolically engineered Clostridia decreases production of acids, thereby increasing the yield of biobutanol (Jang and Lee, 2015).
Clostridium
Published in Yoshikatsu Murooka, Tadayuki Imanaka, Recombinant Microbes for Industrial and Agricultural Applications, 2020
Naotaka Kurose, Kenzo Tonomura
Zeikus has suggested [7] that some thermophilic and ethanologenic Clostridia may be useful for bioethanol production. Clostridium species are spore-forming, anaerobic bacteria with wide ranges of growth temperatures between 30° and 80°C. Some species of Clostridium can produce ethanol, as well as acetic acid and lactic acid, from various sugars such as xylose, glucose, and cellulose. They can directly convert cellulose to ethanol without requiring addition of cellulases. There are, however, two drawbacks in the use of these microorganisms: one is that Clostridium strains produce acetic acid and lactic acid as well as ethanol. Another is that they can tolerate ethanol only up to a concentration of approximately 3%.
Organic Loading
Published in Michael J. Kennish, Ecology of Estuaries: Anthropogenic Effects, 2019
They pose significant health threats to humans who either ingest contaminated shellfish or swim in contaminated water. Among bacteria, the genus Salmonella includes the organism responsible for typhoid, Shigella spp. cause dysentery, and some species of the Clostridia produce exotoxins pathogenic to man.19 Certain viruses in contaminated areas give rise to infectious hepatitis. Sewage treatment, as stated by Capuzzo et al.,9 can lower the number of pathogens in wastewater effluent, specifically during the sludge-forming process. Thermophilic digestion and other sewage treatment techniques have the potential to further reduce the population size of the pathogenic organisms.
Engineering Clostridium acetobutylicum to utilize cellulose by heterologous expression of a family 5 cellulase
Published in Biofuels, 2022
Mary Sanitha, Anwar Aliya Fathima, Andrew C. Tolonen, Mohandass Ramya
Clostridia have been used for industrial solvent production. Clostridium species like C. acetobutylicum, C. beijerinckii, C. saccharoperbutylacetonicum, C. saccharoacetobutylicum, C. aurantibutyricum, C. pasteurianum, C. sporogenes, C. cadaveris and C. tetanomorphum are extensively used for the production of acetone, butanol and ethanol [2]. Among the genus Clostridia, Clostridium acetobutylicum is a well-studied strain that is capable of producing butanol, ethanol and acetone in the ratio 6:3:1. C. acetobutylicum is capable of using a wide range of different fermentable carbohydrates like xylan, levan, pectin and starch [3]. However, it is unable to grow on crystalline cellulose [4], although its genome contains large clusters of genes involved in the cellulolysis process [5]. C. acetobutylicum secretes very small quantities of a cellulosome of approx.665 kDa devoid of activity on crystalline cellulose and possessing very low activity on carboxymethyl cellulose or phosphoric-acid-swollen cellulose [6].
Biobutanol production from cassava waste residue using Clostridium sp. AS3 in batch culture fermentation
Published in Biofuels, 2021
Davidraj Johnravindar, Namasivayam Elangovan, Nellaiappan Olaganathan Gopal, Arunachalam Muthaiyan, Qiang Fei
Different species of solventogenic Clostridia have been examined with respect to biobutanol yield/productivity. Strain AS3 utilised mild acid-hydrolysed CWR, and produced biobutanol. A previous study by Ranjan et al. [31] used Clostridium acetobutylicum MTCC 48 to ferment pre-optimised rice straw hydrolysate and produced 12.22 g L−1 of biobutanol. During ABE production by Clostridium sp. (AS3), the amount of total reducing sugars obtained was 5.97 g L−1. Similarly, Al-shorgani et al. [14] conducted ABE fermentation using rice bran and de-oiled rice bran as carbon source and produced 5.55 and 3.14 g L−1 reducing sugars, respectively. When compared to our CWR the reducing sugar utilisations were found to be quite lower. This might be due to a biological shift of microbes from decline to the spore-forming phase [32, 33]. Hence, the well-known fact of solventogenesis is directly dependent on sporogenesis. Batch fermentation was carried out using T6 medium containing 60 g L−1 mild acid-hydrolysed CWR instead of glucose. After 72 h, 10.78 ± 0.43 g L−1 ABE was obtained from this fermentation, which had the following composition: acetone 0.59 ± 0.21, biobutanol 8.01 ± 0.32 and ethanol 2.18 ± 0.22 g L−1. Similar to our results, butanol production using acid- and enzyme-hydrolysed carbon sources, and their production rates, have previously been reported [34–39] (Table 2).
Developing infant gut microflora and complementary nutrition
Published in Journal of the Royal Society of New Zealand, 2020
Caroline C. Kim, Shanthi G. Parkar, Pramod K. Gopal
In a recent review Korpela and de Vos (2018) provided a global view of the temporal progression of microbiota development in the infant gut during early life. They looked at cumulative data from more than 34 studies conducted in different geographic regions of the world and analysed age-associated changes in the relative abundance of five of the most abundant classes of bacteria in the infant gut. Figure 1 illustrates an age-adjusted evaluation of the average relative abundances in the infant gut from birth to 24 months of age using a subset of the microbiome metadata compiled by Korpela and de Vos. Metadata from 29 studies were used in Figure 1 (data points from infants who had been given antibiotics or who were over the age of 24 months were excluded). Temporal changes in the infant gut microbial populations of key bacterial groups can be clearly observed from these data. Initial colonising bacteria are bacilli (aerobes and facultative aerobes), which give way to colonisation by strict anaerobes such as bifidobacteria and Bacteroides. Bacterial taxa such as Proteobacteria that initially colonise the new-born gut gradually make way for the colonisation of bifidobacteria and Bacteroides and as the complexity of diet increases, there is an increase in relative abundance of Clostridia. While variables such as sample origin (country), birth mode and feeding practices are acknowledged as influencers of the microbial landscape, the age and maturation of the infant gut also influence the microbial colonisation patterns.