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CN-121991843-A - Breeding of bacillus amyloliquefaciens with high temperature tolerance and degradation polyester plastic thereof

CN121991843ACN 121991843 ACN121991843 ACN 121991843ACN-121991843-A

Abstract

The invention relates to breeding of bacillus amyloliquefaciens with high temperature tolerance and polyester plastic degradation thereof. The bacillus amyloliquefaciens H2 (Bacillus thermoamylovorans) is provided, is obtained through step heating adaptive evolution and combined with 80 ℃ heat treatment screening, and can grow at 40-70 ℃ and recover at 50-60 ℃ after being treated for 8-12 hours at 80 ℃. PET is used as the sole carbon source in an inorganic salt culture medium without an exogenous available organic carbon source, and the PET mass loss rate reaches 50.4% when the culture is carried out at 60 ℃ for 30 d. Meanwhile, a microbial preparation containing bacterial cells and/or spores of the strain, a self-degradable polyester material containing spores, a preparation method of the self-degradable polyester material and a biological treatment method for promoting degradation of polyester plastics at 50-70 ℃ are provided. The strain is preserved in China Center for Type Culture Collection (CCTCC) with a preservation number of CCTCC M20252930.

Inventors

  • WU JING
  • YAN ZHENGFEI
  • CAI YIMEI
  • LIU RUIYU
  • ZHANG XINYU
  • CHEN JINHONG
  • YANG WANTING
  • LUO YIHAN

Assignees

  • 江南大学

Dates

Publication Date
20260508
Application Date
20260203

Claims (10)

  1. 1. The high temperature resistant bacillus amyloliquefaciens (Bacillus thermoamylovorans) H2 is characterized in that the strain is preserved in China Center for Type Culture Collection (CCTCC) in 12 months of 2025 and the preservation number is CCTCC M20252930.
  2. 2. The strain H2 according to claim 1, wherein the strain H2 is capable of growing at 40-70 ℃ and is capable of recovering and restoring growth after heat treatment at 80 ℃ for 8-12 hours and transfer to 50-60 ℃ for culture.
  3. 3. Strain H2 according to claim 1 or 2, characterized in that the strain H2 is capable of growing on polyethylene terephthalate (PET) as sole carbon source in inorganic salt medium without exogenously available organic carbon source and when cultivated at 60 ℃ for 30d a mass loss rate of PET is not lower than 40%, wherein the mass loss rate is calculated as (m 0 -m 1 ）/m 0 x 100%, m 0 is the pre-treatment PET mass and m 1 is the post-treatment PET mass.
  4. 4. A method for obtaining the strain H2 of claim 1, comprising the steps of: Culturing a bacillus amyloliquefaciens starting strain at a first temperature T 1 and continuously passaging; After the initial strain grows stably at the first temperature T 1 , gradually increasing the culture temperature to a target temperature T n by steps of 2-5 ℃, and continuously carrying out passage for 5-15 times at each temperature step; Separating single bacterial colony at the target temperature T n and purifying to obtain candidate bacterial strain; carrying out heat treatment at 80 ℃ for 8-12 hours and resuscitating and culturing the candidate strain, and screening to obtain a strain H2 which can still resuscitate and grow after high-temperature treatment; wherein the target temperature Tn is 65-70 ℃.
  5. 5. A microbial preparation is characterized by comprising thalli and/or spores of the strain H2 according to any one of claims 1-3 and an acceptable carrier, wherein the microbial preparation is spore powder, spore suspension or a mixture of the spore powder, spore suspension and auxiliary materials.
  6. 6. A biodegradation method of polyester plastics is characterized in that the strain H2 or the microbial preparation of any one of claims 1-3 and the polyester plastics to be degraded are cultured in contact at 50-70 ℃ to enable the polyester plastics to be biodegraded, wherein an inorganic salt culture medium which does not contain an exogenous available organic carbon source is adopted in the culture, the polyester plastics are used as a sole carbon source, and the polyester plastics at least comprise PET.
  7. 7. The self-degradable polyester material or the self-degradable polyester master batch is characterized by comprising a polyester resin matrix and spores of the strain H2 as claimed in any one of claims 1-3 dispersed in the polyester resin matrix or a surface layer thereof, wherein the polyester resin is selected from PET, PBAT, PBSA, PBST and any combination or blend thereof.
  8. 8. The self-degradable polyester material or the self-degradable polyester master batch according to claim 7, wherein the addition amount of the spores is 0.01-10 wt%.
  9. 9. A process for preparing the self-degradable polyester material or the self-degradable polyester master batch according to claim 7 or 8, which is characterized by comprising the steps of mixing dried bacterial strain H2 spores with polyester resin and/or polyester master batch, and then carrying out melt blending granulation molding or hot press molding to obtain the self-degradable polyester material or the self-degradable polyester master batch.
  10. 10. The use of the strain H2 according to any one of claims 1 to 3 or the microbial preparation according to claim 5 for degrading polyester plastics, wherein the polyester plastics at least comprise PET and the degradation temperature is 50 to 70 ℃.

Description

Breeding of bacillus amyloliquefaciens with high temperature tolerance and degradation polyester plastic thereof Technical Field The invention relates to the technical field of environmental microorganisms and biodegradation, in particular to breeding of high-temperature resistant bacillus amyloliquefaciens (Bacillus thermoamylovorans) and application of the bacillus amyloliquefaciens in degradation and self-degradation materials of polyester plastics (such as PET, PBAT, PBSA, PBST and the like). Wherein PET is polyethylene terephthalate, PBAT is polybutylene terephthalate/adipic acid butanediol copolyester, PBSA is polybutylene succinate/adipic acid butanediol copolyester, and PBST is polybutylene succinate/terephthalic acid butanediol copolyester. Background Polyester plastics such as PET and PBAT, PBSA, PBST are widely applied to the fields of packaging, spinning, agricultural mulching films, engineering materials and the like because of good mechanical properties, barrier properties and processing suitability. However, the polyester material is generally difficult to be obviously degraded in a short period in natural environment, environmental residues are easy to form after being abandoned, and the problems of increased recycling difficulty, limited recycling efficiency and the like are caused. Biodegradation of polyester materials generally involves hydrolysis and/or enzymatic cleavage of ester bonds in the polymer backbone, with degradation rates being closely related to factors such as material crystallinity, surface morphology and specific surface area, hydrophilicity and hydrophobicity, substrate accessibility and mass transfer contact efficiency, and reaction temperature. Generally, in a higher temperature range (for example, 60-70 ℃), the segment mobility of the polyester is enhanced, the interface diffusion and the accessibility of the substrate are improved, the hydrolysis and/or enzymolysis process is facilitated, and meanwhile, engineering scenes such as high-temperature aerobic treatment, composting and the like are always in a higher temperature window, so that higher requirements are placed on the temperature resistance and stability of a degradation system. The polyester degrading microorganisms reported in the prior art are mostly derived from medium-temperature environments, the temperature suitable range is low, and long-term stable growth and continuous maintenance of degradation activity under the condition of 60-70 ℃ are often difficult. In addition, technical routes based in part on enzymatic degradation may suffer from insufficient enzyme stability, activity decay or difficulty in reuse under higher temperature conditions. For polyester materials with higher crystallinity or denser structure, the degradation process may also be limited by interface contact and mass transfer, thereby affecting degradation efficiency and engineering controllability. On the other hand, in order to achieve a technical route for self-degrading materials which "can be biodetected to degrade under specific conditions after use" it is often necessary to coordinate the processing, storage and use of microorganisms, spores or related active systems with the polymeric materials. However, in material molding processing (such as melt extrusion, injection molding, hot pressing, etc.) and subsequent higher temperature environments, the tolerance, survival rate and function retention of microorganisms/spores, and batch repeatability may still be limiting factors, and at the same time, how to achieve controllable triggering, predictable degradation behavior without significantly affecting the mechanical properties and processability of the material, still has engineering implementation difficulties. Therefore, there is a need to obtain heat-resistant microbial resources which can stably grow at 50-70 ℃ (especially 60-70 ℃) and play a role in the degradation process of polyester materials, preferably have the characteristics of resisting high temperature in a spore form and being resuscitatable, and meanwhile, a repeatable, scalable and parameter-controllable breeding/screening route needs to be established so as to obtain strains with degradation promotion effects on various polyester materials such as PET and PBAT, PBSA, PBST, and further form product forms facing engineering applications, including microbial preparations for high-temperature biological treatment and self-degradation polyester systems for realizing in-material accelerated degradation under triggering conditions such as temperature and moisture. Disclosure of Invention Aiming at the problems that the existing polyester degradation microorganism/system is generally insufficient in temperature resistant range, is difficult to stably maintain degradation effect for a long time in a higher temperature window (for example, 50-70 ℃ and especially 60-70 ℃), and engineering realization difficulty still exists in the aspects of processing suitability, hea