Synthesis of a biopolymer via a novel strain of Pantoea as a soil stabilizer

Abstract

Increasing soil stabilization with traditional additives such as cement, which release a high quantity of greenhouse gases during the production, raises environmental concerns. Thus, as a promising alternative for replacing traditional additives, biological processes are emerging as desired green technologies for soil improvement. In this study, a procedure was investigated to improve soil inter-particle cohesion using an environmentally friendly microbial polysaccharide. Further, specific approaches were adopted to reduce the production costs including use of cheap substrates, along with minimizing downstream processing expenses. A novel strain of Pantoea which exhibited a good potential of biopolymer production was isolated from an iron mine. The identification and phylogenetic studies of the isolated strain based on 16S rRNA gen confirmed that the studied strain certainly belongs to Pantoea strain of Enterobacteriaceae. Unconfined compressive strength (UCS) tests confirmed the biopolymer’s potential for clay stabilization. The results indicated that the interaction between the non-extracted biopolymer in the form of cell-free broth (CFB) and soil particles enhanced soil stability. The greatest increase in the UCS was observed in 28 days of curing using 25% CFB/optimum moisture content (OMC), which was 21% more than the UCS value of the untreated soil.