BIODIVERSITAS ISSN: 1412-033X Volume 21, Number 9, September 2020 E-ISSN: 2085-4722 Pages: 4192-4198 DOI: 10.13057/biodiv/d210933 Characterization of a bacteriocin as biopreservative synthesized by indigenous lactic acid bacteria from dadih soya traditional product used in West Sumatra, Indonesia ENDAH RETNANINGRUM 1,♥ , TANIA YOSSI 1 , RINI NUR’AZIZAH 1 , FADILLA SAPALINA 2 , PERISKILA DINA KALI KULLA 2 1 Faculty of Biology, Universitas Gadjah Mada. Jl. Teknika Selatan, Sekip Utara, Sleman 55281, Yogyakarta, Indonesia. Tel./fax. +62-274-580839, Fax.: +62-274-6492355,  email: endahr@ugm.ac.id 2 Graduate Program, Faculty of Biology, Universitas Gadjah Mada. Jl. Teknika Selatan, Sekip Utara, Sleman 55281, Yogyakarta, Indonesia Manuscript received: 9 June 2020. Revision accepted: 20 August 2020. Abstract. Retnaningrum E, Yossi T, Nur'azizah R, Sapalina F, Kulla PDK. 2020. Characterization of a bacteriocin as biopreservative synthesized by indigenous lactic acid bacteria from dadih soya traditional product used in West Sumatra, Indonesia. Biodiversitas 21: 4192-4198. A total of 4 isolates of lactic acid bacteria (strain BDL08, BDL11, BDL12, and BDL13) isolated from dadih soya were investigated for the ability to produce bacteriocin based on their antibacterial activities against Listeria monocytogenes ATCC 7644. Based on comparative 16S rDNA sequencing analysis, isolates BDL 11, BDL12, and BDL13 were identified as Lactobacillus plantarum while the isolates BDL 08 was identified as Leuconostoc mesenteroides. All crude bacteriocins producing strains revealed broad antibacterial spectrum against 7 different indicator bacteria, including Gram-positive and Gram-negative bacteria. L. plantarum BDL11 displayed the highest bacteriocin activity relative to others. The bacteriocin produced by the strain was not affected by pH, heating, and NaCl concentration but was sensitive to proteolytic enzymes. This research indicated that the bacteriocin in the food industry has the potential to be used as a biopreservative. Keywords: 16S rDNA, antibacterial activities, food industry, Lactobacillus plantarum, proteolytic enzyme INTRODUCTION Dadih soya is an Indonesian traditional milk fermentation product that replaced soya milk as a substrate. This product is mainly consumed by people living in West Sumatera, Indonesia. During fermentation process, soya milk is poured into a bamboo tube capped with banana leaves. It is then fermented spontaneously at room temperature for 48 hours by indigenous lactic acid bacteria derived from both of soya milk and bamboo tube. Generally, two species of bamboo, Gombong bamboo (Gigantochloa verticilata) and Ampel bamboo (Bambusa vulgaris) are used in this fermentation process. Lactic acid bacteria contain group of bacteria which play role in the dadih soya fermentation. During this fermentation process, the bacteria can reduce pH value by producing lactic acid. This lactic acid can inhibit undesirable contamination of microorganisms in the product. In addition, these bacteria may produce metabolites such as diacetyl, hydrogen peroxide, some enzymes, antibiotics, reuterin, and bacteriocins (Mazzoli et al. 2014; Fernández-Cruz et al. 2016; Yépez et al. 2017). This bacteria group is characterized as Gram-positive, non- spore-forming cocci, coccobacilli or rods, low G + C content, and non-motile. These bacteria are also characterized by their capability to ferment sugar into lactic acid, catalase-negative, and oxidase-negative (Nguyen et al. 2013; Gänzle et al. 2015; Renschler et al. 2020). Bacteriocins have been the subject of particular interest among the metabolites developed by LAB because of their potential advantages in applying them as natural food biopreservatives (Field 2018; Juturu et al. 2018; Kumariya et al. 2019). These bacteriocins are antimicrobials that are ribosomally synthesized, releasing bioactive peptides or peptide complexes with bactericidal or bacteriostatic effects (Singh et al. 2015; Zou et al. 2018). The advantages of bacteriocins produced by LAB in food preservation have been reported by several researchers. Their properties, including nontoxic to eukaryotic cells, have little influence on the gut microbiota and pH, heat tolerant, have a wide antimicrobial spectrum against many pathogenic food-borne spoilage bacteria and are capable of being bactericidal has attracted number of researchers to investigate this group of bacteria (Yi et al. 2016; Barman et al. 2018). This leads a way to carry out the research to identify LAB producing bacteriocin isolated from dadih soya-based on 16S rDNA gene as molecular marker and to characterize the bacteriocins which would be used as biopreservatives in food products. MATERIALS AND METHODS Sampling and isolation of LAB Samples (dadih soya fermentation) were collected from traditional market in West Sumatera, Indonesia. A 25 g of each sample was added to 225 mL of sterile buffered