Internship Project / Master Thesis: Effects of organic amendments on soil extracellular polymeric substance production and aggregation
1. Background of the study
In natural environment, more than 99% of the life of microbes occur within biofilms. In soil, the development of soil biofilms affects the local soil physico-chemical properties. Biofilms are aggregates of microbes (i.e., bacteria, protozoa, algae, and fungi), connected by extracellular polymeric substance (EPS) which includes up to 80% of a soil biofilm’s dry mass. The EPS of mixed-species biofilms is mainly composed of proteins, carbohydrates/polysaccharides, and uronic acids, with smaller amounts of DNA and glycolipids. The biofilm-secreted extracellular polymeric substance makes up the intercellular space of microbial aggregates, and develops connection among minerals and strengthens the internal cohesion of soil microaggregates. This can protect soil organic matter considerably thereby maintaining both the stability and functioning of the soil structure.
2. Objective and hypothesis of the research
Soil provides habitats to an enormous diversity of microorganisms. The soil microorganisms’ interactions of are of great complexity, and understanding of biofilms in the soil is challenging. Although the protective features of soil biofilms against environmental challenges and the pronounced effect of organic amendments on soil characteristics are generally known, there are still basic questions to be answered. For instance, the mechanisms of biofilm development in soil matrix with the presence of organic amendments, the biological determinants of soil biofilm formation, and the influence of microorganisms originating from organic amendments and their microbial community structures on soil biofilms are greatly unknown. Standardized approaches for characterizing biofilms in soil matrix are also missing. Hence, this research applies artificial soil and investigates the growth of microbes and the production of the soil extracellular polymeric substance with application of various organic amendments comprising compost, bokashi and digestate.
3. Eligibility Criteria
• Background in Environmental Science/ Microbiology /Soil Biology or equivalent;
• Great interests in soil microbiology and organic amendments;
• Good analytical and experimental skills;
• Experiences in microbial laboratory;
• Fluent in English and good English writing skills.
4. Duration, salary and location
• At least 8 months at Wetsus
• Allowance: 175 € per month
• Start: May 1st, 2021
5. Contact Person:
Please contact Yujia Luo (yujia.luo@wetsus.nl) for more information or directly apply by sending your curriculum vitae and motivation letter.
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