Biodegradation of Paper Wastes by Freshwater Snails: Implications for Management

ACS Omega. 2022 Aug 4;7(32):27927-27936. doi: 10.1021/acsomega.2c01653. eCollection 2022 Aug 16.

Abstract

The different types of paper wastes constitute a major portion of municipal solid waste. The present study was aimed to justify the use of freshwater snails for the biological degradation of the paper waste and subsequent availability of cellulose from fecal matter. Three aquatic snails Racesina luteola, Indoplanorbis exustus, and Physella acuta were used to degrade newsprint, cardboard, and common writing paper as paper waste. The consumption of papers by the snail species was subjected to statistical analysis, and the results of Kruskal-Wallis test indicated a significant variation in the paper-specific consumption pattern (K = 181.762, df = 2, p <0.0001) and no variation in the species-specific pattern. Among the three types of paper used for the study, cardboard was consumed at the highest rate (4.655 ± 0.401 mg per day), and the per capita consumption remained highest for the snail I. exustus (2.253 ± 0.273 mg per day). The microscopic images and SEM micrographs of the consumed paper revealed prominent grazing and scraping marks by the snails. The disintegration and relaxation of the papers after consumption indicated that they were on the pathway to degradation. The traditional way of degrading paper waste includes physical, chemical, or microbial treatment of paper pulp. This study represents a novel approach considering the freshwater snails as model organisms for the biodegradation process. Considerable amount of cellulose was present in the fecal samples, which can be extracted and purified for utilization as potent raw material.