Journal of Industrial Microbiology & Biotechnology

, Volume 38, Issue 9, pp 1133–1144 | Cite as

Very high gravity (VHG) ethanolic brewing and fermentation: a research update

  • Pradeep Puligundla
  • Daniela Smogrovicova
  • Vijaya Sarathi Reddy ObulamEmail author
  • Sanghoon Ko


There have been numerous developments in ethanol fermentation technology since the beginning of the new millennium as ethanol has become an immediate viable alternative to fast-depleting crude reserves as well as increasing concerns over environmental pollution. Nowadays, although most research efforts are focused on the conversion of cheap cellulosic substrates to ethanol, methods that are cost-competitive with gasoline production are still lacking. At the same time, the ethanol industry has engaged in implementing potential energy-saving, productivity and efficiency-maximizing technologies in existing production methods to become more viable. Very high gravity (VHG) fermentation is an emerging, versatile one among such technologies offering great savings in process water and energy requirements through fermentation of higher concentrations of sugar substrate and, therefore, increased final ethanol concentration in the medium. The technology also allows increased fermentation efficiency, without major alterations to existing facilities, by efficient utilization of fermentor space and elimination of known losses. This comprehensive research update on VHG technology is presented in two main sections, namely VHG brewing, wherein the effects of nutrients supplementation, yeast pitching rate, flavour compound synthesis and foam stability under increased wort gravities are discussed; and VHG bioethanol fermentation studies. In the latter section, aspects related to the role of osmoprotectants and nutrients in yeast stress reduction, substrates utilized/tested so far, including saccharide (glucose, sucrose, molasses, etc.) and starchy materials (wheat, corn, barley, oats, etc.), and mash viscosity issues in VHG bioethanol production are detailed. Thereafter, topics common to both areas such as process optimization studies, mutants and gene level studies, immobilized yeast applications, temperature effect, reserve carbohydrates profile in yeast, and economic aspects are discussed and future prospects are summarized.


Very high gravity (VHG) Brewing Ethanol fermentation Nutrient supplementation Starch substrates Immobilization Optimization studies 



The present work was supported by the University Grants Commission (UGC), New Delhi, through Major Research Project (MRP) grant, and the Scientific Grant Agency of the Ministry of Education of the Slovak Republic VEGA 1/0096/11.


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Copyright information

© Society for Industrial Microbiology 2011

Authors and Affiliations

  • Pradeep Puligundla
    • 1
  • Daniela Smogrovicova
    • 3
  • Vijaya Sarathi Reddy Obulam
    • 2
    Email author
  • Sanghoon Ko
    • 1
  1. 1.Department of Food Science and TechnologySejong UniversityGwangjin-gu, SeoulKorea
  2. 2.Department of BiochemistrySri Venkateswara UniversityTirupatiIndia
  3. 3.Department of Biochemical Technology, Institute of Biotechnology and Food ScienceSlovak University of TechnologyBratislavaSlovak Republic

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