Assessment of microbial community dynamics in jute-retting ecosystem using Biolog eco plates and GAM analysis

The study evaluated functional microbial community dynamics in jute retting ecosystems across five major jute-growing districts of West Bengal, India, using Community-Level Physiological Profiling (CLPP) with Biolog EcoPlates™ coupled with Generalized Additive Models (GAM). Water samples collected before retting and at peak retting (10th day) were assessed for utilization of 31 carbon substrates over 120 h. Average well color development (AWCD) followed a sigmoidal trend, while the rate of change in AWCD (RAWCD) was significantly higher during retting (54.4-87.2%), indicating intensified microbial metabolism. Shannon-Weaver diversity indices increased significantly during retting, reflecting enhanced functional richness, whereas reduced McIntosh indices (P < 0.01) indicated greater community evenness. Retting-stage communities showed enhanced utilization of carbohydrates, carboxylic acids, amino acids, phenolics, and polymers associated with pectin and hemicellulose degradation. Kinetic analyses demonstrated higher maximum substrate utilization (M), altered slopes (S), and reduced TM₅₀ values for key carbon sources during retting. Kinetic parameters, canonical discriminant analysis, and GAM revealed significant non-linear, location-specific shifts in substrate utilization diversity. The integrated CLPP-GAM approach effectively captured microbial functional restructuring, providing insights for improving retting efficiency while minimizing environmental impacts.