Wastes from bioethanol and beer productions as substrates for l(+) lactic acid production – A comparative study. (February 2016)

• Record Type: Journal Article
• Authors: Djukić-Vuković, Aleksandra; Mladenović, Dragana; Radosavljević, Miloš; Kocić-Tanackov, Sunčica; Pejin, Jelena; Mojović, Ljiljana
• Is Part Of: Waste management. Volume 48(2016)
• Page Start: 478
• Page End: 482
• Publication Date: 2016-02
• Subjects: Lactic acid -- Biorefinery -- Stillage -- Brewers' spent grains -- Probiotics -- Free alpha amino nitrogen; Hazardous wastes -- Periodicals; Refuse and refuse disposal -- Periodicals; 363.728
• DOI: 10.1016/j.wasman.2015.11.031
• Languages: English
• ISSNs: 0956-053X

Abstract

Highlights: Agri-food wastes were studied as substrates for LA and biomass production. Free alpha amino nitrogen (FAAN) positively correlate with LA production on wastes. FAAN could be used for screening of potential waste substrates for LA production. The highest LA productivity (1.54 g L −1 h −1 ) was achieved on wasted bread stillage. Abstract: Waste substrates from bioethanol and beer productions are cheap, abundant and renewable substrates for biorefinery production of lactic acid (LA) and variability in their chemical composition presents a challenge in their valorisation. Three types of waste substrates, wasted bread and wasted potato stillage from bioethanol production and brewers' spent grain hydrolysate from beer production were studied as substrates for the production ofl (+) LA and probiotic biomass by Lactobacillus rhamnosus ATCC 7469. The correlation of the content of free alpha amino nitrogen and the production of LA was determined as a critical characteristic of the waste media for efficient LA production by L. rhamnosus on the substrates which contained equal amount of fermentable sugars. A maximal LA productivity of 1.54 g L −1 h −1 was obtained on wasted bread stillage media, whilst maximal productivities achieved on the potato stillage and brewers' spent grain hydrolysate media were 1.28 g L −1 h −1 and 0.48 g L −1 h −1, respectively. A highest LA yield of 0.91 g g −1 was achieved on wasted bread stillage media, followed by the yield of 0.81 g g −1 on wasted potato stillage and 0.34 g g −1 on brewers' spent grain hydrolysate media. The kinetics of sugar consumption in the two stillage substrates were similar while the sugar conversion in brewers' spent grain hydrolysate was slower and less efficient due to significantly lower content of free alpha amino nitrogen. The lignocellulosic hydrolysate from beer production required additional supplementation with nitrogen.