## 1 Introduction  
A variety of secondary metabolites, including antibiotics, antifungals, and siderophores, are produced by microbes in soil ecosystems to facilitate communication, competition, and interaction with other species in the environment [1]. Few culturable microbial taxa provide the bulk of known antibiotics, and little is known about most soil bacteria's capacity for biosynthesis [1]. The majority of recognized bacterial natural products, including currently used antibiotics, are derived from the microbial isolates of the Actinobacteria, Proteobacteria, and _Bacillus_, which represent microorganisms that frequently form a minority in soil microbial communities [1]. These natural sources avoid the contamination of water and the environment and minimize the risk to animal and human health [2]. Many secondary metabolites with novel antifungal and antibacterial activities from different fungal sources have also been characterized [2]. Secondary metabolites produced by microorganisms cause the effective inhibition of the germination of conidia in various pathogenic fungi [3]. Recent studies reported the inhibitory role of secondary metabolites, including the antagonistic activity against _S. sclerotorium_ and _Alternaria dauci_ fungal pathogens [2]. Fungal illnesses have grown in medical, veterinary, and ecological importance over the last half-century. Globally, the present burden of mycotic illnesses in humans has reached several million cases [4; 5]. A variety of fungi can result in diseases. However, _Candida_ sp. is probably the most commonly observed [6]. The increased use of immunosuppressive medication, invasive surgery, and medical devices in modern medicine has caused a higher prevalence of human fungal infections. Another contributing factor is the frequent use of broad-spectrum antibiotics and antifungal medications. While these drugs are essential for combating bacterial and fungal infections, their extensive use can disrupt the natural balance of microbial communities in the body, thereby increasing the risks of diarrhea and other fatal infections [7]. Collectively, the aforementioned factors have contributed to the ongoing rise of invasive fungal infections, emphasizing the need for enhanced preventive measures, early detection, and targeted treatment strategies to address this global health challenge. The situation became more dangerous and challenging during and after the 2019 coronavirus disease (COVID-19) pandemic, where COVID-19 patients admitted to intensive care units (ICU) had the same risk factors for invasive fungal infections, including chronic respiratory diseases, corticosteroid medication, intubation/mechanical ventilation, cytokine storm, etc. [8]. Many articles indicated co-infection caused by bacteria and fungi in ICU COVID-19 patients, with _Aspergillus_ infections being among them [9; 10]. Mucormy-cosis, also known as \"Black Fungus\", has also been linked to COVID-19 patients, making up approximately 70% of all mucormycosis cases reported [11]. Moreover, when the pre- and post-COVID-19 eras are compared, there is a higher number of candidemia-COVID-19 co-infections [12]. Furthermore, _Aspergillus fumigatus_ has been identified as one of the most common sources of fungal infections in severely ill COVID-19 patients [13]. _Bacillus toyonensis_ is a member of the _Bacillus cereus_ group--it is a spore-forming, Gram-positive organism [14]. It has enormous economic significance; for example, _Bacillus toyonensis_ BCT-7112 spores have been utilized as probiotic supplements in animal nutrition [15]. It was previously reported to exhibit plant growth promotion, biodegradation, and probiotic and biocontrol properties [16; 17; 18]. Its biocontrol properties are rarely reported; however, [PERSON] et al. reported its toyoncin-producing ability. Toyoncin is a bacteriocin (a class of natural macromolecular protein) that is commonly produced by bacteria, e.g., _Bacillus_ spp and _Lactobacillus_ spp [19; 20].