Microbial Utilization of Ramie Gum: A Potential Avenue for Biotechnological Applications

Ramie (Boehmeria nivea) contains approximately 30–35% gum, composed of cellulose, hemicellulose, lignin, pectin, and waxes. This gum is a rich source of carbon and can be utilized as a medium component for microbial growth. The current study was conducted to investigate the mechanism by which Ramie gum stimulates the growth of various bioremediating bacterial strains. The high concentration of total carbohydrate in the Ramie gum substituted Luria–Bertani (LB) broth enhanced the log phase of growth substantially for Bacillus sp. (MCC0008), Micrococcus luteus (SRCHD08), and Pseudomonas sp. (SRCOD5), being cellulase, amylase, and pectinase producing strains. Bacterial strains Brevundimonas diminuta (SRCHD03), Brucella pseudintermedia (SRCHD05), and Ochrobactrum sp. (SRCHD06), which do not produce cellulase, amylase, or pectinase, showed no growth enhancement when Ramie gum was substituted in LB broth. These enzymes (cellulase, amylase, and pectinase) degrade cellulose, hemicellulose, and pectin into sugar compounds that can be utilized by bacteria. The stimulation of biofilm formation may be attributed to the presence of pectin and xylan in the gum, potentially mediated through the Spo0A gene. The strains showing higher growth and biofilm stimulation demonstrated higher bioremediation ability. Thus, the gum discarded during fiber spinning can be effectively valorized as a substrate for bacterial growth.