Physicochemical and microbial analysis of sugarcane press mud reveals ligninolytic and plant growth-promoting bacteria with soil amendment potential

Press mud is an acidic by-product of sugarcane processing that is commonly discarded, despite containing components with potential agricultural value. This study assessed sugarcane mill press mud through physicochemical, microbiological and enzymatic analyses to evaluate its environmental implications and suitability as a soil amendment. The material was slightly acidic (pH 6.4) and rich in essential nutrients, including potassium (1061.06 ppm), magnesium (624.96 ppm), calcium (461.06 ppm) and phosphorus (513.11 ppm). However, elevated metals such as aluminium (2083.22 ppm), iron (2342.57 ppm), manganese (85.90 ppm), zinc (60.84 ppm), copper (17.70 ppm), lead (3.10 ppm) and chromium (4.18 ppm), together with the detection of the pollutant 2,4-di-tert-butylphenol (2,4-DTBP), suggest the need for proper regulated application to mitigate environmental risks. Microbial profiling across acidic (6.4), neutral (7.0) and alkaline (9.5) conditions revealed diverse bacterial taxa. Acidic conditions yielded Escherichia coli (PQ001953), Bacillus licheniformis (PQ001957) and Moraxella catarrhalis (PQ047632); neutral conditions favored Herbaspirillum seropedicae (PQ008927), Enterococcus faecium (PQ012564) and Micrococcus luteus (PQ012569); while alkaline conditions supported Bacillus subtilis (PQ012572), Listeria ivanovii (PQ060442) and Paracoccus pantotrophus (PQ012574). Notably, E. coli, H. seropedicae and M. luteus exhibited pronounced ligninolytic enzyme activity, indicating a capacity to degrade complex organic substrates. Plant growth trials using mustard (Brassica campestris) demonstrated that a 5:1 soil-to-press-mud ratio significantly enhanced plant growth relative to untreated soil. Collectively, these findings indicate that when applied in controlled quantities, press mud, represents a promising bioresource with valuable ligninolytic and plant growth-promoting microbial communities, while warranting careful oversight due to its contaminant load.

This version of the article has been accepted for publication, after peer review (when applicable) and is subject to Springer Nature’s AM terms of use (https://www.springernature.com/gp/open-research/policies/accepted-ma...), but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: http://dx.doi.org/10.1007/s11274-025-04772-2