Bioremediation and toxicity reduction in pulp and paper mill effluent by newly isolated ligninolytic Paenibacillus sp.

The present study deals with the bioremediation of potentially hazardous pulp and paper mill effluent by a laccase producing Paenibacillus sp. strain LD-1 (JX499920) isolated from contaminated soil sample by lignin enrichment method. The bacterium effectively reduced pollution parameters (colour 68%, lignin 54%, phenol 86%, BOD 83% and COD 78%) after 144 h of treatment at 34 ± 1 °C and 120 rpm. GC-MS analysis of control and treated samples showed that concentration of most of the low molecular weight phenolic compounds like 2-methoxyphenol, 2,6-dimethoxy phenol, 2-methoxy-4-ethyl-phenol, 3-allyl-6-methoxyphenol, ethanone 1-(-4-hydroxy-3,5-dimethoxyphenyl), benzoic acid, 2-methoxy-4-(1-propenyl) phenol and 4-methoxycinnamic acid present in control untreated effluent were reduced after bacterial treatment. The toxicity assessments were carried out with treated and untreated effluent by studying the growth and germination of seeds of mung bean (Vigna radiata L.). The mung bean bioassay confirmed the detoxification of effluent after bacterial treatment.