A Process Study of Lactic Acid Production from Phragmites australis Straw by a Thermophilic Bacillus coagulans Strain under Non-Sterilized Conditions

Phragmites australis straw (PAS) is an abundant and renewable wetland lignocellulose. Bacillus coagulans IPE22 is a robust thermophilic strain with pentose-utilizing capability and excellent resistance to growth inhibitors. This work is focused on the process study of lactic acid (LA) production from P. australis lignocellulose which has not been attempted previously. By virtue of thermophilic feature of strain IPE22, two fermentation processes (i.e., separated process and integrated process), were developed and compared under non-sterilized conditions. The integrated process combined dilute-acid pretreatment, hemicellulosic hydrolysates fermentation, and cellulose utilization. Sugars derived from hemicellulosic hydrolysates and cellulose enzymatic hydrolysis were efficiently fermented to LA in a single vessel. Using the integrated process, 41.06 g LA was produced from 100 g dry PAS. The established integrated process results in great savings in terms of time and labor, and the fermentation process under non-sterilized conditions is easy to scale up for economical production of lactic acid from PAS.

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Statistical Optimization of Dilute Acid Hydrolysis of Wood Sawdust for Lactic Acid Production

Journal of Applied Biotechnology & Bioengineering ◽

10.15406/jabb.2017.04.00093 ◽

2017 ◽

Vol 4 (1) ◽

Cited By ~ 1

Author(s):

Aicha Nancib

Keyword(s):

Lactic Acid ◽

Acid Hydrolysis ◽

Acid Production ◽

Lactic Acid Production ◽

Statistical Optimization ◽

Dilute Acid ◽

Dilute Acid Hydrolysis ◽

Wood Sawdust ◽

Hydrolysis Of

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Lipid Production by Cryptococcus curvatus on Hydrolysates Derived from Corn Fiber and Sweet Sorghum Bagasse Following Dilute Acid Pretreatment

Applied Biochemistry and Biotechnology ◽

10.1007/s12010-014-1007-y ◽

2014 ◽

Vol 173 (8) ◽

pp. 2086-2098 ◽

Cited By ~ 23

Author(s):

Yanna Liang ◽

Kimberly Jarosz ◽

Ashley T. Wardlow ◽

Ji Zhang ◽

Yi Cui

Keyword(s):

Sweet Sorghum ◽

Lipid Production ◽

Corn Fiber ◽

Dilute Acid Pretreatment ◽

Sweet Sorghum Bagasse ◽

Dilute Acid ◽

Cryptococcus Curvatus ◽

Acid Pretreatment ◽

Sorghum Bagasse

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Understanding the effects of different residual lignin fractions in acid-pretreated bamboo residues on its enzymatic digestibility

Biotechnology for Biofuels ◽

10.1186/s13068-021-01994-y ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Wenqian Lin ◽

Jinlai Yang ◽

Yayue Zheng ◽

Caoxing Huang ◽

Qiang Yong

Keyword(s):

Enzymatic Hydrolysis ◽

Negative Impact ◽

Dilute Acid Pretreatment ◽

Residual Lignin ◽

Dilute Acid ◽

Enzymatic Digestibility ◽

Acid Pretreatment ◽

Organic Reagents ◽

Milled Wood Lignin ◽

Affinity Constants

Abstract Background During the dilute acid pretreatment process, the resulting pseudo-lignin and lignin droplets deposited on the surface of lignocellulose and inhibit the enzymatic digestibility of cellulose in lignocellulose. However, how these lignins interact with cellulase enzymes and then affect enzymatic hydrolysis is still unknown. In this work, different fractions of surface lignin (SL) obtained from dilute acid-pretreated bamboo residues (DAP-BR) were extracted by various organic reagents and the residual lignin in extracted DAP-BR was obtained by the milled wood lignin (MWL) method. All of the lignin fractions obtained from DAP-BR were used to investigate the mechanism for interaction between lignin and cellulase using surface plasmon resonance (SPR) technology to understand how they affect enzymatic hydrolysis Results The results showed that removing surface lignin significantly decreased the yield for enzymatic hydrolysis DAP-BR from 36.5% to 18.6%. The addition of MWL samples to Avicel inhibited its enzymatic hydrolysis, while different SL samples showed slight increases in enzymatic digestibility. Due to the higher molecular weight and hydrophobicity of MWL samples versus SL samples, a stronger affinity for MWL (KD = 6.8–24.7 nM) was found versus that of SL (KD = 39.4–52.6 nM) by SPR analysis. The affinity constants of all tested lignins exhibited good correlations (r > 0.6) with the effects on enzymatic digestibility of extracted DAP-BR and Avicel. Conclusions This work revealed that the surface lignin on DAP-BR is necessary for maintaining enzyme digestibility levels, and its removal has a negative impact on substrate digestibility.

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Development of Four Unit Processes for Biobased PLA Manufacturing

ISRN Polymer Science ◽

10.5402/2012/938261 ◽

2012 ◽

Vol 2012 ◽

pp. 1-6 ◽

Cited By ~ 4

Author(s):

Chae Hwan Hong ◽

Si Hwan Kim ◽

Ji-Yeon Seo ◽

Do Suck Han

Keyword(s):

Lactic Acid ◽

Ring Opening ◽

Lactic Acid Production ◽

Scale Up ◽

Catalyst System ◽

Ring Opening Polymerization ◽

Acid Fermentation ◽

Manufacturing Method ◽

Renewable Biomass ◽

Microbial Productivity

Polylactide (PLA), which is one of the most important biocompatible polyesters that are derived from annually renewable biomass such as corn and sugar beets, has attracted much attention for automotive parts application. The manufacturing method of PLA is the ring-opening polymerization of the dimeric cyclic ester of lactic acid, lactide. For the stereocomplex PLA, we developed the four unit processes, fermentation, separation, lactide conversion, and polymerization. Fermentation of sugars to D-lactic acid is little studied, and its microbial productivity is not well known. Therefore, we investigated D-lactic acid fermentation with a view to obtaining the strains capable of producing D-lactic acid, and we got a maximum lactic acid production 60 g/L. Lactide is prepared by a two-step process: first, the lactic acid is converted into oligo(lactic acid) by a polycondensation reaction; second, the oligo(lactic acid) is thermally depolymerized to form the cyclic lactide via an unzipping mechanism. Through catalyst screening test for polycondensation and depolymerization reactions, we got a new method which shortens the whole reaction time 50% the level of the conventional method. Poly(L-lactide) was obtained from the ring-opening polymerization of L-lactide. We investigated various catalysts and polymerization conditions. Finally, we got the best catalyst system and the scale-up technology.

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