Construction of in situ degradation bacteria of corn straw and analysis of its degradation efficiency

Xiujie Gong,Chunrong Qian,Yubo Hao,Qiuju Wang,Yubo Jiang,Hongtao Zou,Yang Yu,Juntao Ma,Liang Li

doi:10.1186/s13213-020-01601-9

Abstract

PurposeThe highly efficient degradation bacteria were selected from the humus from the very cold straw in China for many years to construct the in situ degradation bacteria, and the degradation efficiency of corn straw was determined by process optimization.MethodsAccording to the main components of corn straw, through morphological, physiological, and biochemical screening, three highly efficient complementary degradation strains were selected to construct the compound flora, and the degradation efficiency was analyzed by Fourier transform infrared spectrometer, field emission scanning electron microscope, and X-ray diffractometer.ResultThe corn straw selected in this paper is mainly composed of cellulose (31.99%), hemicellulose (25.33%), and lignin (14.67%). Through the determination of enzyme activity, strain Streptomyces sp. G1T has high decomposition ability to cellulose and hemicellulose but weak utilization ability to lignin; strain Streptomyces sp. G2T has the strongest decomposition ability to cellulose and hemicellulose among the three strains. The decomposition ability of strain Streptomyces sp. G3T to lignin was the strongest among the three strains. Therefore, by compounding the three strains, the decomposition ability has been greatly improved. The optimal process conditions obtained by single factor and response surface method are as follows: pH is 7, temperature is 30 °C, inoculation amount is 5%, rotational speed is 210 rpm, and the weight loss rate of straw is 60.55% after decomposing for 7 days. A large amount of degradation of corn straw can be seen by Fourier transform infrared spectrometer, field emission scanning electron microscope, and X-ray diffractometer.ConclusionStreptomyces sp. G1T, Streptomyces sp. G2T, and Streptomyces sp. G3T screened from straw humus in very cold areas were used to construct in situ degradation bacteria, which had good straw degradation activity and had the potential to be used for straw treatment in cold areas after harvest. This characteristic makes the complex bacteria become a strong competitive candidate for industrial production, and it is also an effective biotechnology in line with the current recycling of resources.

Highlights

China, as a traditional agricultural country in the world, produces more than 600 million tons of straw every year
Degradation efficiency analysis The degradation efficiency was analyzed by Fourier transform infrared spectrometer (Thermo Fisher Scientific Nicolet 6700), field emission scanning electron microscope (QUANTA FEG 250), and X-ray diffractometer (UltimaIV SmartLab)
According to the experimental results, it can be seen that the main components of corn straw are cellulose, namely cellulose, hemicellulose, and lignin (Table 1)

Summary

Introduction

As a traditional agricultural country in the world, produces more than 600 million tons of straw every year. Because the corn straw is mainly composed of lignocellulose, if it is not treated, it is difficult to be degraded by microorganisms in the natural field, so that the straw is decomposed and transformed by microorganisms in the soil for a long time, and the soil fertility effect will not be achieved immediately. It even affects the farming of crops in the season, which is not attractive to farmers (Chen et al 2002; Xu et al 2001). In the winter paddy field in the south, after the corn straw is returned to the field, the content of methane released from the paddy field will be doubled, which has attracted great attention of the environmental circle (Sabine et al 2001; Liou et al 2003; Lu et al 2010)

Methods

Results

Conclusion