In this study a preparation strategy was attempted to produce a substitute (BBF) for the Ruditapes philippinarum conglutination mud (RPM), which was newly discovered to be a promising natural bioflocculant resource. A stable yield of 73.77 ± 1.79 g L−1 BBF was established by a sequential batch fermentation under optimized conditions via single factor experiments. BBF attained similar flocculation performance as RPM, showing a maximum flocculation rate of 87.92 ± 0.65%. BBF had significant decolorization efficiency on methylene blue, crystal violet and malachite green by 98.78 ± 0.46%, 89.37 ± 0.35% and 99.11 ± 0.17%, respectively. BBF could harvest microalgae Chlorella salina by 84.38 ± 0.57%. High throughput sequencing revealed that Vibrio and Bacillus might be the extracellular polysaccharides producers. The successful preparation will enable a potential industrial production of BBF thus avoid scattered collection of RPM.