Conversion of aqueous ammonia-treated corn stover to lactic acid by simultaneous saccharification and cofermentation

Extremely low-liquid ammonia (ELLA) pretreatment using aqueous ammonia was investigated in order to enhance the enzymatic saccharification of corn stover and subsequent ethanol production. In this study, corn stover was treated with an aqueous ammonia solution at different ammonia loading rates (0.1, 0.2, and 0.3 g NH3/g biomass) and various liquid-to-solid (L/S) ratios (0.55, 1.12, and 2.5). The ELLA pretreatment was conducted at elevated temperatures (90–150 °C) for an extended period (24–120 h). Thereafter, the pretreated material was saccharified by enzyme digestion and subjected to simultaneous saccharification and fermentation (SSF) tests. The effects of key parameters on both glucan digestibility and xylan digestibility were analyzed using analysis of variance (ANOVA). Under optimal pretreatment conditions (L/S = 2.5, 0.1 g-NH3/g-biomass, 150 °C), 81.2% glucan digestibility and 61.1% xylan digestibility were achieved. The highest ethanol yield achieved on the SSF tests was 85.4%. The ethanol concentration was 14.5 g/L at 96 h (pretreatment conditions: liquid-to-solid ratio (L/S) = 2.5, 0.1 g-NH3/g-biomass, 150 °C, 24 h. SSF conditions: microorganism Saccharomyces cerevisiae (D5A), 15 FPU/g-glucan, CTech2, 3% w/v glucan, 37 °C, 150 rpm).

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Biodetoxification of Phenolic Inhibitors from Lignocellulose Pretreatment using Kurthia huakuii LAM0618T and Subsequent Lactic Acid Fermentation

Molecules ◽

10.3390/molecules23102626 ◽

2018 ◽

Vol 23 (10) ◽

pp. 2626 ◽

Cited By ~ 6

Author(s):

Yuejiao Xie ◽

Qing Hu ◽

Guodong Feng ◽

Xu Jiang ◽

Jinlong Hu ◽

...

Keyword(s):

Lactic Acid ◽

Corn Stover ◽

Simultaneous Saccharification And Fermentation ◽

High Titer ◽

Bacillus Coagulans ◽

High Yield ◽

Acid Fermentation ◽

Biochemical Production ◽

Water Rinsing ◽

Simultaneous Saccharification

Phenolic inhibitors generated during alkaline pretreatment of lignocellulosic biomasses significantly hinder bacterial growth and subsequent biofuel and biochemical production. Water rinsing is an efficient method for removing these compounds. Nevertheless, this method often generates a great amount of wastewater, and leads to the loss of solid fiber particles and fermentable sugars. Kurthia huakuii LAM0618T, a recently identified microorganism, was herein shown to be able to efficiently transform phenolic compounds (syringaldehyde, hydroxybenzaldehyde, and vanillin) into less toxic acids. Taking advantage of these properties, a biodetoxification method was established by inoculating K. huakuii LAM0618T into the NH3/H2O2-pretreated unwashed corn stover to degrade phenolic inhibitors and weak acids generated during the pretreatment. Subsequently, 33.47 and 17.91 g/L lactic acid was produced by Bacillus coagulans LA204 at 50 °C through simultaneous saccharification and fermentation (SSF) from 8% (w/w) of NH3/H2O2-pretreated corn stover with or without K. huakuii LAM0618T-biodetoxification, indicating biodetoxification significantly increased lactic acid titer and yield. Importantly, using 15% (w/w) of the NH3/H2O2-pretreated K. huakuii LAM0618T-biodetoxified corn stover as a substrate through fed-batch simultaneous saccharification and fermentation, high titer and high yield of lactic acid (84.49 g/L and 0.56 g/g corn stover, respectively, with a productivity of 0.88 g/L/h) were produced by Bacillus coagulans LA204. Therefore, this study reported the first study on biodetoxification of alkaline-pretreated lignocellulosic material, and this biodetoxification method could replace water rinsing for removal of phenolic inhibitors and applied in biofuel and biochemical production using the alkaline-pretreated lignocellulosic bioresources.

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High-Titer Lactic Acid Production by Pediococcus acidilactici PA204 from Corn Stover through Fed-Batch Simultaneous Saccharification and Fermentation

Microorganisms ◽

10.3390/microorganisms8101491 ◽

2020 ◽

Vol 8 (10) ◽

pp. 1491

Author(s):

Zhenting Zhang ◽

Yanan Li ◽

Jianguo Zhang ◽

Nan Peng ◽

Yunxiang Liang ◽

...

Keyword(s):

Lactic Acid ◽

Corn Stover ◽

High Efficiency ◽

Simultaneous Saccharification And Fermentation ◽

High Titer ◽

Lactic Acid Production ◽

Pediococcus Acidilactici ◽

Fed Batch ◽

Ssf Process ◽

Simultaneous Saccharification

Lignocellulose comprised of cellulose and hemicellulose is one of the most abundant renewable feedstocks. Lactic acid bacteria have the ability to ferment sugar derived from lignocellulose. In this study, Pediococcus acidilactici PA204 is a lactic acid bacterium with a high tolerance of temperature and high-efficiency utilization of xylose. We developed a fed-batch simultaneous saccharification and fermentation (SSF) process at 37 °C (pH 6.0) using the 30 FPU (filter paper units)/g cellulase and 20 g/L corn steep powder in a 5 L bioreactor to produce lactic acid (LA). The titer, yield, and productivity of LA produced from 12% (w/w) NaOH-pretreated and washed stover were 92.01 g/L, 0.77 g/g stover, and 1.28 g/L/h, respectively, and those from 15% NaOH-pretreated and washed stover were 104.11 g/L, 0.69 g/g stover, and 1.24 g/L/h, respectively. This study develops a feasible fed-batch SSF process for LA production from corn stover and provides a promising candidate strain for high-titer and -yield lignocellulose-derived LA production.

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