¹H NMR Quantitative Assessment of Lactic Acid Produced by Biofermentation of Cane Sugar Juice

ABSTRACT

The demand for lactic acid as a raw material for the chemical industry is on the rise. Various lactic acid bacteria (LAB) have been tested for the fermentation of sugar-cane juice and molasses into lactic acid. Industrially, the most commonly used producer strains are from the Lactobacillus genus. We report here on the fermentation of sugar-cane juice and syrup into L-lactic acid using Lactobacillus delbrueckii subsp delbrueckii (NCIM 2365). We present a reliable method to quantitatively assess the amount of L-lactic acid produced during fermentation using ¹H NMR spectroscopy. This analytical method offers various advantages over existing ones and can be extended to the on-line monitoring of fermentation of sugars into lactic acid in industry.

KEYWORDS:

• ¹H NMR spectroscopy
• lactic acid
• quantitative assessment

ACKNOWLEDGMENTS

The authors are most grateful to Beau Champ Sugar Estate (Mauritius) for providing the sugar-cane mixed juice and syrup. The technical support and advice of Dr G. Khittoo (Dept. of Biosciences, University of Mauritius) and Mr. S. Puchooa (Dept. of Agricultural and Food Science, University of Mauritius) are gratefully acknowledged.

Notes

An invited paper submitted to a special issue on Green Spectroscopy and Analytical Techniques, organized by Professor Miguel de la Guardia, of the Department of Chemistry, University of Valencia, Spain, and Professor Arabinda Kumar Das, of the Department of Chemistry, University of Burdwan, West Bengal, India.