Polyphenols content of spent coffee grounds subjected to physico-chemical pretreatments influences lignocellulolytic enzymes production by Bacillus sp. R2
The objective of this study was to investigate the impact of polyphenols content changes issued a... more The objective of this study was to investigate the impact of polyphenols content changes issued after physico-chemical treatments of spent coffee grounds on lignocellulolytic enzymes production by Bacillus sp. R2. Total polyphenols of the collected substrates were extracted with water under autoclaving conditions. Results showed that polyphenols content of spent coffee grounds decreased with continued treatments. Untreated spent coffee grounds were the best substrate for cellulase and pectinase (1.33 ± 0.06 μ/ml and 0.32 ± 0.02 μ/ml respectively). A strong positive correlation was noticed between polyphenols content and cellulase and pectinase activities. However, xylanase and peroxidase correlated moderately with polyphenols content and their highest activities were registered with spent coffee grounds treated with boiling water and 1% EDTA (0.31 ± 0.002 μ/ml and 15.56 ± 0.56 μ/ml respectively). The obtained results indicate that polyphenols content of the pretreated substrates influences the production of lignocellulolytic enzymes by Bacillus sp. R2.
In the current study two different strains of Bacillus (Bacillus sp. R2 and Bacillus cereus 11778... more In the current study two different strains of Bacillus (Bacillus sp. R2 and Bacillus cereus 11778) were used in single and mixed culture to study the co-production of cellulases and manganese peroxidases using waste newspaper as a sole carbon source. The highest level of cellulases production was noticed after 24 h in the mixed culture (1.08 ± 0.02 FPU mg-1). While the lowest production was observed also in the mixed culture after 72 h of incubation (0.47 ± 0.03 FPU mg-1). For the peroxidases production we noticed that Bacillus sp. R2 and the mixed culture have shown an important capacity to produce peroxidases. A strong positive correlation between cellulase and Mn peroxidase was detected in Bacillus sp. R2, In Bacillus cereus there was no correlation detected, while in the mixed culture we noticed that cellulase has a strong negative correlation with Mn peroxidase. The obtained results showed a remarkable dyes decolorization. Concerning Methylene blue the highest level of decolourization was noticed in Bacillus cereus (47%). For neutral red the degree of decolourization was around 80% and that for all cultures. Finally, for Congo red decolourization has reached his maximum level after only 135 min of reaction for the three cultures (69%, 69% 72% respectively).
Cellulosic biomass is considered as one of the most promising sources for the production of alter... more Cellulosic biomass is considered as one of the most promising sources for the production of alternative renewable bioenergy and other valuable products. The abundance of cellulosic waste such as agricultural, industrial and forest waste, and the need for their biodegradation and their bioconversion into fermentable sugars, has increased the demands for more effective cellulase producing microorganisms. For this purpose, the present study was conducted to isolate thermophilic cellulolytic microorganisms. 111 thermophilic microorganisms (91 bacteria and 20 yeasts) were isolated from 10 western Algerian sources (thermal and non-thermal) and tested for the production of cellulase. The results revealed the presence of 19 thermophilic cellulolytic isolates. Macroscopic and microscopic examination has indicated the presence of 16 thermophilic bacteria and 3 thermophilic yeasts. These isolates were tested for the degradation of cellulosic biomass (printable paper, filter paper and cotton) for 14 days of incubation at 60°C. The obtained results showed a great potential of these thermophilic cellulolytic microorganisms to produce thermostable cellulolytic enzymes, and can be used in the recycling of cellulosic biomass for bioenergy production after optimization studies in the future.
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