Investigation of nutrient feeding strategies in a countercurrent mixed-acid multi-staged fermentation: Development of segregated-nitrogen model

Smith, Aaron; Holtzapple, Mark T.

doi:10.1016/j.biortech.2010.07.072

Cited by 9 publications

(3 citation statements)

References 21 publications

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“…Also, a faintly noticeable lag phase implies that the initial composition of stillage/molasses media was appropriate for LAB growth. Many studies have shown that carbon/nitrogen (C/N) ratio considerably influences LA yield and cell growth . In the study of Akao et al .…”

Section: Resultsmentioning

confidence: 99%

Lactic acid production on a combined distillery stillage and sugar beet molasses substrate

Mladenović

Djukić‐Vuković

Kocić‐Tanackov

et al. 2015

J of Chemical Tech & Biotech

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BACKGROUND: Utilization of wastes and industrial by-products for production of valuable bio-based chemicals has economic and environmental advantages. The aim of this study was to investigate utilization of two industrial by-products, distillery stillage and sugar beet molasses combined as a substrate for lactic acid and biomass production. A selection of the most appropriate lactic acid bacteria that could effectively utilize this waste substrate was performed. In addition, the effect of initial sugar concentration on lactic acid production and growth of lactic acid bacteria on the combined waste substrate was evaluated. RESULTS:Lactobacillus paracasei NRRL B-4564 was selected as the most promising for lactic acid production on distillery stillage and sugar beet molasses. The highest lactic acid productivity of 1.42 g L −1 h −1 and yield of 0.91 g g −1 were achieved on stillage/molasses media at initial sugar concentration of 56.74 g L −1 . The highest number of L. paracasei cells at 5.3 × 10 9 CFU mL −1 was achieved at initial sugar concentration of 78.22 g L −1 . CONCLUSION: Combined distillery stillage and sugar beet molasses could provide valuable nutrients for growth of fastidious lactic acid bacteria and enable efficient lactic acid production, while processing industrial waste in this way has great environmental relevance.

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Section: Resultsmentioning

confidence: 99%

Lactic acid production on a combined distillery stillage and sugar beet molasses substrate

Mladenović

Djukić‐Vuković

Kocić‐Tanackov

et al. 2015

J of Chemical Tech & Biotech

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“…The nitrogen properties of the feedstocks, the operating parameters, the solid-liquid separation efficiency, and the nutrient-rich substrate-loading pattern influence the behavior of nitrogen in a countercurrent fermentation, which dictates performance. Based on this paper, Smith and Holtzapple [32] introduced a segregatednitrogen model that may be used to predict/optimize nitrogen concentration profiles for a four-bottle train.…”

Section: Yieldmentioning

confidence: 99%

Investigation of Nutrient Feeding Strategies in a Countercurrent Mixed-Acid Multi-Staged Fermentation: Experimental Data

Smith

Lockman

Holtzapple

2011

Appl Biochem Biotechnol

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Nutrients are essential for microbial growth and metabolism in mixed-culture acid fermentations. Understanding the influence of nutrient feeding strategies on fermentation performance is necessary for optimization. For a four-bottle fermentation train, five nutrient contacting patterns (single-point nutrient addition to fermentors F1, F2, F3, and F4 and multi-point parallel addition) were investigated. Compared to the traditional nutrient contacting method (all nutrients fed to F1), the near-optimal feeding strategies improved exit yield, culture yield, process yield, exit acetate-equivalent yield, conversion, and total acid productivity by approximately 31%, 39%, 46%, 31%, 100%, and 19%, respectively. There was no statistical improvement in total acid concentration. The traditional nutrient feeding strategy had the highest selectivity and acetate-equivalent selectivity. Total acid productivity depends on carbon-nitrogen ratio.

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“…To keep the performance of an acidogenic digester stable, pH buffer addition is required to neutralize the increasing VFAs and to counteract the pH decrease [10]. In previous studies, sodium carbonate and bicarbonate (Na 2 CO 3 and NaHCO 3 ) [11], calcium carbonate (CaCO 3 ) [12], and ammonium bicarbonate (NH 4 HCO 3 ) [13] have been used as pH buffers for anaerobic fermentations. The objectives of this study were to find an optimum pH range and to identify a buffer addition method for butyric acid production from rice straw.…”

Section: Introductionmentioning

confidence: 99%

Butyric Acid Fermentation from Rice Straw with Undefined Mixed Culture: Enhancement by pH Control

Xue

et al. 2013

AMR

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This study aimed to find out the optimum pH range and a buffer feeding method for butyric acid production from rice straw by undefined mixed culture. A serial experiment was conducted at various pH levels from 5.0 to 7.0. The results showed that neutral pH improved rice straw conversion and hence carboxylic acid production. The highest butyric acid production was achieved at pH range of 6.0 to 6.5. Another serial experiment was performed at pH 6.0 to 6.5 buffered with CaCO3, NaHCO3, NH4HCO3 and their combinations, respectively. The results indicated that different buffers had different effects on product spectrum, and that CaCO3 combined with NaHCO3 was an effective buffer for butyric acid production. This study presents an alternative way for butyric acid production from lignocellulosic biomass without supplementary cellulolytic enzyme.

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Investigation of nutrient feeding strategies in a countercurrent mixed-acid multi-staged fermentation: Development of segregated-nitrogen model

Cited by 9 publications

References 21 publications

Lactic acid production on a combined distillery stillage and sugar beet molasses substrate

Lactic acid production on a combined distillery stillage and sugar beet molasses substrate

Investigation of Nutrient Feeding Strategies in a Countercurrent Mixed-Acid Multi-Staged Fermentation: Experimental Data

Butyric Acid Fermentation from Rice Straw with Undefined Mixed Culture: Enhancement by pH Control

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