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A novel cellulase-producing actinomycete strain Gxj-6T, isolated from soil in the cold region (Heihe city, Heilongjiang province, the northernmost part of China), subjected to a taxonomic study using a polyphasic approach. In the neighbour-joining phylogenetic tree based on 16S rRNA gene sequences, strain Gxj-6T fell within the clade comprising the type strains of species of the genus Microbispora. 16S rRNA gene sequence similarity studies exhibited that species Gxj-6T was most closely related to Microbispora bryophytorum NEAU-TX2-2T (99.45%), Microbispora fusca NEAU-HEGS1-5T (99.41%), Microbispora camponoti 2C-HV3T (99.31%) and Microbispora rosea subsp. rosea JCM 3006T (98.68%). Organism Gxj-6T contained MK-9(H2) as the predominant ubiquinone and C18:0 10-methyl as the major fatty acid. The major polar lipids of culture Gxj-6T were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol mannoside, three unidentified phospholipids, two unidentified glycolipids and two unidentified lipids. The DNA G+C content of strain Gxj-6T was 71.25 mol%. The morphological and chemotaxonomic properties of the strain are also consistent with those members of the genus Microbispora. Combinated with the lower DNA–DNA relatedness values, phenotypic properties, physiology and biochemistry distinctiveness with other recognized species strains, revealed that strain Gxj-6T is separated from other phylogenetically closely species of the genus Microbispora. Therefore, strain Gxj-6T is considered to represent a novel species of the genus Microbispora, for which the name Microbispora cellulosiformans sp. nov. is proposed. The type strain is Gxj-6T (= CGMCC 4.7605T = DSM 109712T).

Purpose The 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. Methods According 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. Result The 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. Conclusion Streptomyces 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.