Production, purification, and characterization of cellulase from Acinetobacter junii GAC 16.2, a novel cellulolytic gut isolate of Gryllotalpa africana, and its effects on cotton fiber and sawdust

Sandipan Banerjee,Tushar Kanti Maiti,Raj Narayan Roy

doi:10.1186/s13213-020-01569-6

Abstract

PurposeThe study aims to search for potent cellulase producer from the gut of Gryllotalpa africana as well as to characterize and determine the effect of the purified enzyme on the cellulosic waste materials.MethodsThe potent cellulolytic strain was identified through morphological, biochemical, physiological, and molecular characterization like 16S rRNA and fatty acid methyl ester profile. After the optimization of cellulase production, the enzyme was purified through DEAE-Sepharose column chromatographic separation. The molecular weight of the purified enzyme was determined by SDS-PAGE analysis. The purified enzyme was characterized in terms of its activity and its effect on cotton fiber, and sawdust was also studied.ResultThe selected potent strain GAC 16.2 was identified as Acinetobacter junii that was capable to produce enhanced cellulase (112.38 ± 0.87 U/ml) at standardized optimum fermentation conditions. The molecular weight of the purified enzyme was determined as 55 kDa. The utmost activity of the purified enzyme was detected pH 7.0, temperature 50 °C, and in the presence of metal ions like Mg2+ and Mn2+. The substantive degradation of cotton fiber and sawdust has been observed in a reasonably short period.ConclusionPurified cellulase from the selected isolate A. junii GAC16.2, a gut isolate of G. africana, has the potentiality to degrade cellulosic substances. This property can make the isolate a potent candidature for industrial application, as well as an effective biotechnological tool for environmental monitoring through cellulosic waste management.

Highlights

Cellulose is the most abundant renewable organic molecule on the earth (Klemm et al 2005)
Purified cellulase from the selected isolate A. junii GAC16.2, a gut isolate of G. africana, has the potentiality to degrade cellulosic substances. This property can make the isolate a potent candidature for industrial application, as well as an effective biotechnological tool for environmental monitoring through cellulosic waste management
Collection of insects To check the presence of the cellulase-producing gut bacteria of Gryllotalpa africana, the insects were collected from the different potato fields and agro-waste dumps located at the Gangetic plain of West Bengal, India

Summary

Introduction

Cellulose is the most abundant renewable organic molecule on the earth (Klemm et al 2005). The resultant reducing sugars could be used for the production of desired value-added byproducts (Sukumaran et al 2005; Octave and Thomas 2009) This enzyme is extensively consumed in paper and pulp industries, in textile industry, for the production of biofuel, as an anti-biofilm agent, for waste management in pharmaceutical industries, for pollution control, and in food as well as in feed industries (Sreena et al 2016; Aarti et al 2018; Thomas et al 2018; Sreena and Sebastian 2018). In the course of evolution, these symbiotic associations between insects and different microorganisms have been deeply rooted (Moran and Telang 1998) These symbionts exhibit beneficial activities for their hosts. One such activity is the production of various important hydrolytic enzymes including cellulase. Though only a few detail studies have been made concerning the enzyme-producing insect gut bacteria, it requires further observations (Dillon and Dillon 2004)

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