https://www.sbmicrobiologia.org.br/PDF/industrial.pdf

Glycerol: A promising and abundant carbon source for industrial microbiology

http://ehsan13967.persiangig.com/document/glycerol1.pdf

Anaerobic fermentation of glycerol: a path to economic viability for the biofuels industry.

Recent advances in lactic acid production by microbial fermentation processes

Today, biomass covers about 10% of the world's primary energy demand. Against a backdrop of rising crude oil prices, depletion of resources, political instability in producing countries and environmental challenges, besides efficiency and intelligent use, only biomass has the potential to replace the supply of an energy hungry civilisation. Plant biomass is an abundant and renewable source of energy-rich carbohydrates which can be efficiently converted by microbes into biofuels, of which, only bioethanol is produced on an industrial scale today. Biomethane is produced on a large scale, but is not yet utilised for transportation. Biobutanol is on the agenda of several companies and may be used in the near future as a supplement for gasoline, diesel and kerosene, as well as contributing to the partially biological production of butyl-t-butylether, BTBE as does bioethanol today with ETBE. Biohydrogen, biomethanol and microbially made biodiesel still require further development. This paper reviews microbially made biofuels which have potential to replace our present day fuels, either alone, by blending, or by chemical conversion. It also summarises the history of biofuels and provides insight into the actual production in various countries, reviewing their policies and adaptivity to the energy challenges of foreseeable future.

Biofuels from microbes.

Given the current robust forces driving sustainable production, and available biomass conversion technologies, biomass-based routes are expected to make a significant impact on the production of bulk chemicals within 10 years, and a huge impact within 20–30 years. In the Port of Rotterdam there is a clear short-term (0–10 year) substitution potential of 10–15 % of fossil oil-based bulk chemicals by bio-based bulk chemicals, especially for oxygenated bulk chemicals, such as ethylene glycol and propylene glycol, iso-propanol and acetone, butylene and methylethylketone and for the replacement of methyl tertiary butyl ether (MTBE) by ethyl tertiary butyl ether (ETBE). Glycerin, as a byproduct of biodiesel production, is a very favorable short-term option for the production of ethylene and propy-lene glycols in the Port of Rotterdam. In the mid-term (10–20 years) there is clear potential for a bio-based production of ethylene, acrylic acid and N-containing bulk chemicals such as acrylonitrile, acrylamide and e-caprolactam. Technologies involving direct isolation of aromatic building blocks from biomass, or the conversion of sugars or lignin to aromatics are still in their infancy. Biorefineries that are being started up today will form the stepping stones toward the chemicals mentioned above if we learn to upgrade their side streams. For main ports like the Port of Rotterdam, these developments imply that it has to consider in much closer detail those facilities it has to offer for a more bio-based chemistry and economy. © 2007 Society of Chemical Industry and John Wiley & Sons, Ltd

/pdf/bulk-chemicals-from-biomass-27wcebe46y.pdf

Bulk chemicals from biomass

Pilot-scale production of 1,3-propanediol using Klebsiella pneumoniae

Statistical optimization of culture conditions for 1,3-propanediol by Klebsiella pneumoniae AC 15 via central composite design.

1,3-Propanediol production by Klebsiella pneumoniae was studied in batch cultures under N2 flow and four airflow systems. Different byproducts were formed under different aeration conditions. An anaerobic/aerobic combined fed-batch culture was developed giving 70 g 1,3-propanediol l−1 and 16 g 2,3-butanediol l−1 with total diol yield of 0.6 mol−1 glycerol.

1,3-Propanediol production by Klebsiella pneumoniae under different aeration strategies.

BACKGROUND: The crude glycerol from biodiesel production represents an abundant and inexpensive source which can be used as raw material for lactic acid production. The first aim of this investigation was to select a strain suitable for producing lactic acid from glycerol with a high concentration and productivity. The second aim was to obtain the optimum fermentation conditions, as a basis for large-scale lactate production in the future.



RESULTS: Eight bacterial strains, which could aerobically convert glycerol to lactic acid, were screened from soil samples. One of the strains, AC-521, which synthesized lactic acid with a higher concentration, was identified based on its 16S rDNA sequences and physiological characteristics. These results indicated that this strain was a member of Escherichia coli. The optimal fermentation conditions for Escherichia coli AC-521 were 42 °C, pH 6.5, 0.85 min−1 (KLa).



CONCLUSION:Escherichia coli AC-521 suitable for producing lactic acid from glycerol with high concentration and productivity was identified. After 88 h of fed-batch fermentation, both the lactic acid concentration and glycerol consumption reached maximum, giving 85.8 g L−1 of lactic acid with a productivity of 0.97 g L−1 h−1 and a yield of 0.9 mol mol−1 glycerol. Copyright © 2009 Society of Chemical Industry

Strain isolation and optimization of process parameters for bioconversion of glycerol to lactic acid

Broth containing 152 g glycerol l−1 from Candida krusei culture was converted to 1,3-propanediol by Klebsiella pneumoniae. Residual glucose in the broth promoted growth of K. pneumoniae while acetate was inhibitory. After desalination treatment of glycerol broth by electrodialysis, the acetate in the broth was removed. A fed-batch culture with electrodialytically pretreated broth as␣substrate was developed giving 53 g 1,3-	propanediol l−1 with a yield of 0.41 g g−1 glycerol and a productivity of 0.94 g l−1 h−1.

Yan Sun

Papers

Pilot-scale production of 1,3-propanediol using Klebsiella pneumoniae

Statistical optimization of culture conditions for 1,3-propanediol by Klebsiella pneumoniae AC 15 via central composite design.

1,3-Propanediol production by Klebsiella pneumoniae under different aeration strategies.

Strain isolation and optimization of process parameters for bioconversion of glycerol to lactic acid

Production of 1,3-propanediol by Klebsiella pneumoniae from glycerol broth