Selection of the Strain Lactobacillus acidophilus ATCC 43121 and Its Application to Brewers' Spent Grain Conversion into Lactic Acid.

Rossana Liguori,Loredana Marcolongo,Carlos Ricardo Soccol,Adenise Lorenci Woiciechowski,Elena Ionata,Vincenza Faraco,Luciana Porto De Souza Vandenberghe

doi:10.1155/2015/240231

Rossana Liguori, Loredana Marcolongo + Show 5 more

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https://doi.org/10.1155/2015/240231

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Abstract

Six Lactobacillus strains were analyzed to select a bacterium for conversion of brewers' spent grain (BSG) into lactic acid. Among the investigated strains, L. acidophilus ATCC 43121 showed the highest yield of lactic acid production (16.1 g/L after 48 hours) when grown in a synthetic medium. It was then analyzed for its ability to grow on the hydrolysates obtained from BSG after acid-alkaline (AAT) or aqueous ammonia soaking (AAS) pretreatment. The lactic acid production by L. acidophilus ATCC 43121 through fermentation of the hydrolysate from AAS treated BSG was 96% higher than that from the AAT treated one, although similar yields of lactic acid per consumed glucose were achieved due to a higher (46%) glucose consumption by L. acidophilus ATCC 43121 in the AAS BSG hydrolysate. It is worth noting that adding yeast extract to the BSG hydrolysates increased both the yield of lactic acid per substrate consumed and the volumetric productivity. The best results were obtained by fermentation of AAS BSG hydrolysate supplemented by yeast extract, in which the strain produced 22.16 g/L of lactic acid (yield of 0.61 g/g), 27% higher than the value (17.49 g/L) obtained in the absence of a nitrogen source.

Highlights

Bioconversion of lignocellulosic residual biomass can make a significant contribution to the production of organic biochemicals [1]
The lactic acid bacteria (LAB) Lactobacillus acidophilus ATCC 53672, L. acidophilus ATCC 43121, L. acidophilus ATCC 4356, L. lactis INRA 18, L. pentosus NRRL B-227, and L. plantarum NRRL B-4496 were compared for their lactic acid production ability in a synthetic medium
The maximum yield of lactic acid per substrate consumed (YP/S) value varied from a minimum of 0.52 g/g for the strain L. pentosus NRRL B-227 to a maximum of 0.99 g/g for L. acidophilus ATCC 43121, followed by the strains L. acidophilus ATCC 53672, L. plantarum NRRL B-4496, L. acidophilus ATCC 4356, and L. lactis INRA 18 with YP/S of 0.98 g/g, 0.96 g/g, 0.95 g/g, and 0.70 g/g, respectively

Summary

Introduction

Bioconversion of lignocellulosic residual biomass can make a significant contribution to the production of organic biochemicals [1]. Huge amounts of lignocellulosic wastes are produced yearly all around the world They include agricultural residues, food farming wastes, green-grocer’s wastes, tree pruning residues, and the organic and paper fractions of urban solid wastes. One of the most important organic compounds is lactic acid, recognized as a GRAS (generally recognized as safe) compound by the US FDA (Food and Drug Administration), with many applications in food, cosmetics, and pharmaceutical and chemical industries [2]. It has received a great deal of attention as a feedstock monomer for the production of PLA (polylactic acid), used as a biodegradable commodity plastic

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