## 4 Discussion  
The research--obtained and evaluated microbial macro-components produced by _Bacillus_ sp., representative of the following key components, active whole cells, spores, enzymes, bio-polymers, and sticking agents for potential soil stabilisation application. The selection of _B. licheniformis_ for cultivation at 10 L scale was due to its previous use as an industry product and its production of extracellular substances of interest [24]. Due to its documented use as a stabiliser, it is a logical starting point to investigate the bio-stabilising properties of various fermentation derived macro-components. Two separate batches were harvested at specific time points from the fermentation, as the aging process was hypothesised to increase the production of extracellular components of benefit. An extraction technique was performed on each fermentation harvest (i.e., vegetative and sporulation) with the aim of potentially extracting \"sticky agents\"/bio-polymers from the various components (i.e., whole fermentation broth, supernatant, vegetative cells, and spores). The extracellular substances (mixture of unknown compounds) extracted from each component were defined by the method used to separate the macro-components (i.e., polar compounds--aqueous extraction, and non-polar compounds--non-polar extraction). The selected method is consistent with general extraction to whole cell bacteria and bio-transformation that requires a hydrophobic solvent and exhibits higher biocatalyst compatibility [18]. In the study's first phase, development of the upstream processing (USP) and downstream processing (DSP) technology provided a fit for purpose process. The result from this phase of the study showed the production of multiple test fractions that can be used as starting material for the small-scale strength testing. This process can be repeated using various other microbes and bio-based testing components. Therefore, at a later stage the scale up studies include optimizing the fermentation conditions for maximum EPS production (which will then require detailed isolation), analysis, identification, and characterisation of polymeric substances from _B. licheniformis_. In the area of EPS production by [PERSON] et al. [11] high EPS production by _B. licheniformis_ (strain HYTAPB18) showed  
Figure 8: SEM-EDX micrographs showing (**a,b**) showing (**a**) EDX elemental composition, and (**b**) SEM image analysed showing fine material micro-aggregates between the grains. a better aggregation effect with a larger bacterial population size and larger incubation periods for EPS production which results in a soil aggregation effect. In the second phase, the impact of all the fractions of the fermentation material was tested for the desired effect for soil stabilisation. The rationale for this study was that one or more components (fractions) of the fermentation material show resistance to: abrasion, erosion, compression, and exhibit water absorptive properties. For the testing of the macro-components and fractions, a series of small-scale strength tests enabled assessment of the multiple samples in a high-throughput method, to select the best performing fractions. The statistical evaluation (i.e., quantification of multiple effects/structural criteria into test matrices) was used to measure the criteria of interest, regarding the structural stabilisation of the selected soil material and enabled the selection of the best performing fractions. In detail, the performance of disintegration resistance (water resistance properties) was better in stabilised soil. As with a previous investigation the stabilised soil remained cohesive and minimally deformed over the short time [25], which was attributed to the agglomeration of soil particles into larger units in the stabilised soil samples. Furthermore, the stabilised soil type i (dolerite) treated with the non-aqueous prototypes namely, (b2) and (e2) showed significant resistance to water erosion.