# From Waste to Strength: Applying Wastepaper, Fungi and Bacteria for Soil Stabilization
## 4 Conclusions  
One of the main objectives of this study was to determine the optimal amount of wastewater to be introduced into soil treated with microbially induced calcite precipitation (MICP), continuing our previous work [29]. Additionally, we investigated the potential of using the ureolytic bacteria _Bacillus licheniformis_ DSMZ 8782 and the yeast-like fungus _Scytalidium candidium_ 3C for soil stabilization, both individually and in combination.  
The experimental results showed that the optimal amount of wastewater paper to be added was 2%, both for soil samples treated with the bacterial suspension of _B. licheniformis_ and for soil samples where the natural biomineralizing microorganisms were involved. At  
Figure 5: Results of whole-genome sequencing analysis of soil samples (with read overlap greater than 0.3%).  
this concentration, the wastewater did not hinder the biomineralization process, while it enhanced the strength of the samples through reinforcement with the wastewater fibers.  
Treatment with fungal biomass led to a significant increase in strength in the Fng soil sample, which did not contain wastewater. Its strength increased nearly ninefold compared to the control (236.6 kPa vs. 26.4 kPa) and almost fourfold compared to the bacterial treatment (236.6 kPa vs. 60.63 kPa). However, the introduction of wastewater into the Fng samples led to a decrease in strength, which correlated with a reduction in the calcium carbonate content.  
The high strength of the Mix soil samples (with 0% and 2% wastewater) treated with a combination of bacterial and fungal biomasses--compared to both the Control and Bact samples with the same wastewater content--can be attributed not only to the increased calcium carbonate content, which is characteristic of traditional MICP treatment, but also to the synergistic effects of the reinforcing wastewater fibers and the mineralizing activity of the microorganisms, including the not entirely clear effect of fungal biomass.  
Furthermore, we found that the addition of the mycelial fungus _Sc. candidum_ to the soil samples led to an increased proportion of bacterial strains capable of biomineralization, particularly from the genus _Lysinibacillus_. Thus, the introduction of _Sc. candidum_ into the MICP process yielded promising results in terms of soil strength enhancement, suggesting it could be a valuable addition to the treatment process and merits more detailed study.  
Conceptualization, D.A.G. and A.A.K.; formal analysis, I.M.L. and A.T.S.; investigation, D.A.G., I.M.L., E.V.Z. and M.V.B.; methodology, D.A.G., I.M.L. and E.V.Z.; project administration, A.A.K.; supervision, A.A.K.; visualization, D.A.G. and I.M.L.; writing--original draft, I.M.L.; writing--review and editing, D.A.G., I.M.L. and A.A.K. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Genome Research Centre development program \"Kurchatov Genome Centre-PNPI\" (agreement no. 075-15-2019-1663).  
Not applicable.  
The data presented in this study are available on request from the corresponding author in accordance with the State regulations and appropriate laws.  
The authors gratefully thank [PERSON] and [PERSON] for the scanning electron microscopy, [PERSON] for the DNA extraction assistance and [PERSON] for the valuable discussion of the results.  
The authors declare no conflicts of interest.