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

Yuming Zhang,Mengran Li,Zhihua Ni,Tian Nie

doi:10.3390/pr6100175

Abstract

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.

Highlights

Lactic acid (LA) is an important chemical commodity with versatile applications in food, chemicals and pharmaceutical industries [1]
B. coagulans IPE22 was used in the present work
The present work is focused on study of lactic acid production process using Phragmites australis straw (PAS), Inhas conclusion, present previously

Summary

Introduction

Lactic acid (LA) is an important chemical commodity with versatile applications in food, chemicals and pharmaceutical industries [1]. The studies on converting lignocellulosic feedstock into. LA were extensively reported [2,3,4]. Phragmites australis straw (PAS) is an abundant and renewable lignocellulosic feedstock with worldwide distribution [5]. In China, there are at least 0.67 million hectares for planting P. australis, with a PAS output of more than 3 million ton [6]. Large scale output of PAS offers a huge potential as a renewable resource for LA production. Lignocellulose, including PAS, consists primarily of cellulose, hemicellulose, and lignin [7]

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Discussion

Conclusion