en تخصصي Special Original article Original article <div style="text-align: justify;"><span style="font-size:14px;"><span style="font-family:Times New Roman;"><span style="line-height:115%"><b><span lang="EN"><span style="line-height:115%">Background: </span></span></b><span lang="EN"><span style="line-height:115%">Spontaneous is an effective method to enhance the bioactivity and stability of foods through the action of Lactic Acid Bacteria (LAB), the dominant microbes in this fermentation which generate antimicrobial metabolites, while also serving as a form of biological preservation. <i>Hypsizygus</i> sp., an edible mushroom valued for its high nutritional value, is highly perisable and benefits from biological preservation strategies. This study investigated LAB isolated from spontaneous fermentation of <i>Hypsizygus</i> sp. and characterized their bacteriocin-like inhibitory activity.</span></span></span><br> <span style="line-height:115%"><b><span lang="EN"><span style="line-height:115%">Methods:</span></span></b><span lang="EN"><span style="line-height:115%"> Spontaneous fermentation was performed on<i> Hypsizygus</i> sp. using 2% NaCl, 1% sucrose, 3% chili pepper, and 2% garlic then incubated for 6 days at 27&plusmn;1 &deg;C. LAB were isolated on days 0, 2^nd, 4^th, and 6^th using de Man, Rogosa, and Sharpe agar (MRSA) medium, and characterized through colony and cell morphology, catalase activity, carbohydrate fermentation, and tolerance to salt and temperature. Bacteriocin-like inhibitory substances activity and stability were evaluated for antibacterial activity and stability across temperature, pH, and proteolytic enzyme treatment. Statistical analysis used two-way ANOVA followed by Sidak&rsquo;s post-hoc test (<i>p</i><0.05).<span style="background:#d9ead3"></span></span></span></span><br> <span style="line-height:115%"><b><span lang="EN"><span style="line-height:115%">Results:</span></span></b><span lang="EN"><span style="line-height:115%"> Four isolates exhibited promising traits, with ISL-2A and ISL-4G&mdash;identified as belonging to the genus <i>Lactobacillus</i>&mdash;demonstrating the highest antibacterial activity against <i>Staphylococcus aureus</i> and <i>Escherichia coli</i>. The bacteriocin-like inhibitory substances produced were stable across a pH range of 3.0&ndash;7.0 and temperatures up to<br> 80 &deg;C, but were inactivated by proteolytic enzyme.</span></span></span><br> <b><span lang="EN"><span style="line-height:115%">Conclusion: </span></span></b><span lang="EN"><span style="line-height:115%">These findings underscore the potential of LABs derived from fermented <i>Hypsizygus</i> sp. as natural antimicrobials and biopreservatives for food.</span></span><br> <br> <span style="line-height:normal"><b><span lang="EN">DOI:</span></b><span lang="EN"> 10.18502/jfqhc.12.4.20407</span></span></span></span><span style="font-size:11pt"><span style="line-height:normal"><span style="font-family:Arial,&quot;sans-serif&quot;"><span lang="EN" style="font-family:&quot;Times New Roman&quot;,&quot;serif&quot;"></span></span></span></span></div> Anti-Bacterial Agents, Bacteriocins, Fermentation, Food Preservation 293 300 http://jfqhc.ssu.ac.ir/browse.php?a_code=A-10-1950-1&slc_lang=en&sid=1 N.A. Putri 0009-0008-6260-9168 No Faculty of Biology, Universitas Gadjah Mada, Jl Teknika Selatan, Sekip Utara Yogyakarta 52281, Indonesia S. Darmasiwi saridarma@ugm.ac.id 0000-0002-6179-5500 Yes Faculty of Biology, Universitas Gadjah Mada, Jl Teknika Selatan, Sekip Utara Yogyakarta 52281, Indonesia