## 1 Introduction  
Biofilms are well-structured, nourished, and self-protected multicellular communities of sessile microbes embedded in an extracellular polymeric matrix [1]. Biofilms can be harmful or beneficial depending on the causative organism [2]. Biofilm-associated infections caused by bacterial or yeast pathogens have been frequent and recurrent threats to humans [3, 4]. In several microbial pathogens, biofilm formation is a crucial defense mechanism that often facilitates virulence genes expression and may promote developing resistance to antimicrobial chemotherapy. Therefore, the biofilm mode of growth displays recalcitrant behavior, and exhibits increased tolerance to antibiotics [5], which often leads to the failure of antibiotic therapy and the evolution of multi-drug resisting microbial variants.  
Current thinking in the field of biofilm research dictates of need for developing novel approaches to mitigating biofilm formation [6]. Innovative treatment involves using small-molecule inhibitors that either block microbial adhesion, prevent inter- or intracellular microbial communications, or disrupt pre-formed biofilms [7, 8]. Lately, such small-molecule inhibitors are being increasingly viewed as potential antibiofilm pharmaceuticals. Thus, studies to identify or/and develop new antibiofilm pharmaceuticals are rapidly intensifying. Another streamlined approach to treating pathogenic biofilms is probiotic therapy [9]. Probiotics are live microorganisms that are supposed to be beneficial in enhancing human welfare [10]. Lactic acid bacteria (LAB) are the most popular probiotics shown to eradicate pathogens by the competitive-exclusion principle [11], i.e., LAB may compete with and successfully eliminate the pathogenic species. For example, in the human vaginal environment, LAB are natural competitors of the yeast pathogen _Candida albicans_[12]. Aided by the low pH of the vaginal environment, LAB may robustly suppress _C. albicans_ infection. LAB can also secrete a myriad of volatile compounds or secondary metabolites that may assist in their antagonistic activities against pathogens [13; 14].  
_Lactobacillus plantarum_ is a prospective probiotic bacterium with a Qualified Prevention of Safety (QPS) and a Generally Recognized as Safe (GRAS) status [15]. Thus, _L. plantarum_ has often been used as bio-control measures against foodborne pathogens [16]. In addition, cell-free supernatant of _L. plantarum_ cultures has been shown to inhibit the growth of _Listeria monocytogenes_, _Salmonella enteritidis_, _Escherichia coli_ O157:H7, and _Staphylococcus aureus_[17; 18]. Secondary metabolites such as organic acids, bacterioxins, and other antimicrobial peptides secreted by _L. plantarum_ in its culture filtrates may account for the observed antimicrobial effects [19; 20; 21]. Recently, a probiotic _L. plantarum_ MG98 strain was shown to inhibit _E. coli_ or _C. albicans_ during coculture assays [17; 22]. This strain also prevented yeast adhesion and colonization on HT-29 cells, thus explaining the importance of _L. plantarum_ as a biocontrol against _Candidia_ infections.  
In addition, postbiotics and metabolic byproducts of probiotics from _Lactobacillus_ species were shown to reduce biofilm formation by several pathogens, including _Aggregatbacter actinomycetemmitans_, _Pseudomonas aeruginosa_, and _Listeria monocytogenes_[23; 24; 25; 26; 27]. In the current study, we aimed to characterize the antagonistic activities of postbiotics from _L. plantarum_ colonies against microbial pathogens, such as _E. coli_, _S. aureus_, and _C. albicans_. Our findings indicate the promising role of the postbiotics prepared from _Lactobacillus plantarum_ colonies in the development of antibioticIM pharmaceuticals. Furthermore, the findings also provide _in vitro_, _in vivo_, and _in silico_ proof-of-concept for applying bocillary postbiotics, including one of its active compounds, 2-undecanone, as a potent antibiofilm and anti-hyphal agent.