Biodegradation and hydrolysis of rice straw with corn steep liquor and urea-alkali pretreatment

Yulin Ma; Xu Chen; Muhammad Zahoor Khan; Jianxin Xiao; Shuai Liu; Jingjun Wang; Gibson Maswayi Alugongo; Zhijun Cao

doi:10.3389/fnut.2022.989239

Biodegradation and hydrolysis of rice straw with corn steep liquor and urea-alkali pretreatment

Front Nutr. 2022 Aug 4:9:989239. doi: 10.3389/fnut.2022.989239. eCollection 2022.

Authors

Yulin Ma¹, Xu Chen¹, Muhammad Zahoor Khan^{1

2}, Jianxin Xiao¹, Shuai Liu¹, Jingjun Wang¹, Gibson Maswayi Alugongo¹, Zhijun Cao¹

Affiliations

¹ State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China.
² Department of Animal Breeding and Genetics, Faculty of Veterinary and Animal Sciences, University of Agriculture, Dera Ismail Khan, Pakistan.

Abstract

The current study evaluated the corn steep liquor (CSL) and urea-alkali pretreatment effect to enhance biodegradation and hydrolysis of rice straw (RS) by ruminal microbiome. The first used RS (1) without (Con) or with additives of (2) 4% CaO (Ca), (3) 2.5% urea plus 4% CaO (UCa) and (4) 9% corn steep liquor + 2.5% urea + 4% CaO (CUCa), and then the efficacy of CSL plus urea-alkali pretreatment was evaluated both in vitro and in vivo. The Scanning electron microscopy, X-ray diffraction analysis, cellulose degree of polymerization and Fourier-transform infrared spectroscopy, respectively, results showed that Ca, UCa, and CUCa pretreatment altered the physical and chemical structure of RS. CSL plus Urea-alkali pretreated enhanced microbial colonization by improving the enzymolysis efficiency of RS, and specially induced adhesion of Carnobacterium and Staphylococcus. The CUCa pretreatment could be developed to improve RS nutritional value as forage for ruminants, or as feedstock for biofuel production.

Keywords: CSL and urea-alkali pretreatment; corn steep liquor; enzymatic hydrolysis; rice straw; ruminal bacteria.