Screening and identification of indigenous cellulolytic bacteria from Indonesian coffee pulp and investigation of its caffeine tolerance ability

ABSTRACT

Aims: The objective of the research was to get the potential cellulolytic bacteria which was caffeine tolerance from Indonesian coffee pulp waste. Methodology and results: The cellulolytic bacteria were isolated from coffee pulp wastes of Coffea arabica and C. canephora. These isolates were selected based on their cellulose hydrolysis, CMCase activity, and caffeine tolerance. The density of cellulolytic bacteria of C. arabica pulp waste was 4.7 ± 3.5 × 106 CFU/g, and that of C. canephora pulp waste was 1.5 ± 1.5 × 106 CFU/g. Among 61 cellulolytic bacterial isolates, 24 isolates formed clear zones on CMC medium with Gram iodine flooding. Three isolates (CRM10, CRM1, and CRM12) from C. canephora pulp waste had the highest cellulolytic activity. Based on the CMCase activity, it was indicated that an isolate of CRM10 showed the highest CMCase activity with 3.38 ± 0.65 U/mL. This bacteria had tolerance ability to caffeine until 0.4% on nutrient agar medium. Isolates of CRM10 had similarity to Bacillus subtilis based on 16S rDNA sequence. Conclusion, significance, and impact of study CRM10 was identified as Bacillus subtilis and considered as a potential isolate to degrade cellulose of coffee pulp waste that contained caffeine. .