## 4 Discussion  
The germination index (GI) was used to evaluate the phytotoxic substances present in the compost, which is one of the most sensitive parameters that accounts for the low toxicity affecting root growth [38]. The _Bacillus_ sp. strains were tested for their potential plant-growth-promoting function, and SB-3 and SB-4 were selected for the composting process. _Bacillus_ sp. is known to enhance the availability of macro- and micronutrients in the soil and their uptake by host plants [39]. Enhancement in the maximum proximate chemical constituents including carbohydrate, proteins, dry matter, etc., was recorded by the application of _Bacillus_ sp. [PERSON] et al. [39] identified the significant role of _Bacillus_ isolates in the enhancement in essential amino-acid contents and other nutritive chemical constituents in food crops [40]. The seed germination and plant growth of radish and  
Figure 9: Antioxidant activity of leaf extracts of pepper plants grown in soil amended with the functional SCG composts carrying _Streptomyces sasae_ St-3 and infected with root rot plant pathogens _Fusarium oxysporum_ f. sp. _lactuce_ (KACC 42795) (FO) and _Pythium ultimum_ (KACC 40705) (PU). The tests included (**a**) DPPH scavenging activity, (**b**) total phenolic content (TPC), (**c**) total flavonoid content (TFC), and (**d**) Trolox equivalent antioxidant activity (TEAC). Letters above the error bar indicates the comparison of samples using [PERSON]’s test. pepper plants are significantly influenced by the nutrients available in the soil. The results of the two different plants confirms the difference between the several potential microbes tested in this process (Figure 2). Plants absorb phosphorus (P) and nitrogen (N) from the soil through root transporters, but the bioavailable forms of P and N are limited in rhizosphere [41]. _Bacillus_ sp. convert the complex form of essential nutrients, such as P and N, to a simple available form that is used during uptake by plant roots [42; 43]. Phosphate is involved in nucleic acid, phospholipid, and adenosine triphosphate (ATP) metabolism, among other metabolic pathways, in plant cells [44]. The secretion of phosphatases and organic acids from _Bacillus_ sp. acidifies the surrounding environment to facilitate the conversion of inorganic phosphate into free phosphate [42; 45]. In this study, _Bacillus cereus_ SB-3 (KCTC14418 BP) and _Bacillus toyonensis_ SB-4 (KCTC14417 BP) appeared to promote the growth of radish. The genomic analysis of plant-associated _B. cereus_ 905 showed that the genes related to plant-growth-promoting traits were highly conserved [46]. _B. cereus_ SA1 inoculation increased the biomass, chlorophyll content, and chlorophyll fluorescence of soybean plants under normal and heat stress conditions. The SA1 strain can be used as a good temperature-tolerant candidate for the mitigation of heat stress damage in soybean plants and can be commercialized as a biofertilizer [45]. _Bacillus toyonensis_ COPE52 was reported to produce indoleacetic acid and protease activity, and emit volatiles such as acetoin, 2,3-butanediol, and dimethyl disulfide as potential plant-growth-promoting mechanisms, leading to growth in biomass and chlorophyll content in blueberry plants [47]. _B. toyonensis_ COPE52 also showed plant-growth-promoting activities including indole-3-acetic acid (IAA), protease activity, and biofilm formation, as well as antifungal activity against _Botrytis cinerea_, even in saline conditions [48]. Analysis of the inhibitory effect of _Streptomyces sasae_ St-3 on the plant pathogenic fungi revealed its potential antifungal activity (Figure 3). This acidophilic characteristic of _Streptomyces_ sp. may help it to adapt to the soil conditions. Moreover, a recent study found that the antifungal activity of _Streptomyces_ inhibits fungi including _Fusarium oxysporum, Pythium apanidermatum, P. ultimum_, _Rhizoctonia solani_, _Sclerotium rolsii_, _Sclerotium minor_, and _S. sclerootium_, and other soil-borne plant pathogens [49].