Statistical optimization of cellulases by Talaromyces thermophilus utilizing Saccharum spontaneum, a novel substrate

BACKGROUND: At present, cellulases are the most important enzymes worldwide, and their demand has been increasing in the industrial sector owing to their notable hydrolysis capability. RESULTS: In the present study, contrary to conventional techniques, three physical parameters were statistically optimized for the production of cellulase by thermophilic fungi by using response surface methodology (RSM). Among all the tested thermophilic strains, the best cellulase producing fungus was identified as Talaromyces thermophilus ­ both morphologically and molecularly through 5.8S/ITS rDNA sequencing. The central composite design (CCD) was used to evaluate the interactive effect of the significant factors. The CCD was applied by considering incubation period, pH, and temperature as the model factors for the present investigation. A second-order quadratic model and response surface method revealed that the independent variables including pH 6, temperature 50 C, and incubation period 72 h significantly influenced the production of cellulases. The analysis of variance (ANOVA) indicated that the established model was significant (P 0.05) and showed the high adequacy of the model. The actual and predicted values of CMCase and FPase activity showed good agreement with each other and also confirmed the validity of the designed model. CONCLUSIONS: We believe the present findings to be the first report on cellulase production by exploiting Kans grass (Saccharum spontaneum) as a substrate through response surface methodology by using thermophilic fungus, Talaromyces thermophilus.

Bioethanol production from urban cellulosic waste employing Alcaligenes faecalis HI-1 isolated from gut of termite Heterotermes indicola

This study assessed the potential of termite gut inhabiting bacteria towards bioconversion of cellulosic waste into biofuel. Total seven bacterial isolates from the gut of Heterotermes indicola were isolated. Among all the isolates, HI-1 produced the largest zone upon primary screening. Untreated paper had more cellulose content (73.03%) than acid (0.5%) treated paper that was used as a lignocellulosic substrate for saccharification. Among all the isolates tested, glucose yield (1.08mg/mL) was high for HI-1 isolate. Several factors were considered for optimizing augmented glucose yield (8.57mg/mL) and growth (8.07×108cfu/mL), such as temperature 37°C, pH 4.5, 5% (w/v) substrate concentration, 6 % bacterial inoculum size, agitation 150 rpm with PEG 0.25 % and Ca2+ ions 0.002 g/L. Overall 8-fold increase in glucose yield was achieved. Enzyme activity of HI-1 showed higher endoglucanase 0.29 ± 0.01 (U/mL/min) and exoglucanase 0.15±0.01 (U/mL/min) activity under optimum conditions, mentioned above. temperature 37°C, pH 4.5, substrate concentration 5%, inoculum size 6%, surfactants PEG 0.01%, ions Ca2+(0.002g/L) and agitation (120 rpm). Simultaneous saccharification and fermentation (SSF) of hydrolyzed office paper yielded 5.43mg/mL bioethanol. According to 16S rRNA sequence homology, the bacterial isolate H1 was identified as Alcaligenes faecalis. Bioethanol production from office paper untreated waste proved an effective strategy. Bacteria having natural tendency towards cellulosic waste consumption are promising for bioconversion of cellulosic waste to valuable products.

Evaluation of microbial potential and ripening behavoiur of preclimacteric bananas following gamma irradiation / Avaliação do potencial microbiana e amadurecem comportamento de bananas preclimacteric seguinte irradiação gama

The current study was carried out to evaluate the effects of gamma irradiation on the epiphytic microflora and ripening process of the green Dwarf Cavendish bananas harvested at the three-quarter stage of the maturity. The mature green bananas were irradiated using Cobalt-60 as the source of irradiation at different dosages of 0.5, 0.75 and 1.0 kGy. The mean life of both the experimental and control group of fruits was analyzed under ambient conditions. For all the treatments the microbial potential, the decay percent and the ripening behavior of the fruits were recorded. Results revealed that the applied radiation doses reduced the decay incidence, delayed ripening process and greatly inhibit the microbial growth (total bacterial and fungal count) thereby enhancing the shelf life of bananas. Irradiation dose of 1.0 kGy was found to be the most effective dose to positively maintain the stored bananas under ambient conditions. The mean life of bananas was extended by 14 days. The identification of the enteric bacteriaeaceae through API 20 E strips revealed the presence of Shigella sonnie on the fruit surface along with Escherichia coli and a nonfermentor spp. The dominant spoilage causing fungi identified were Aspergillus niger, Aspergillus flavus, Collotrichum musae, Fusarium oxysporum,Mucor spp, Lasiodiplodia theobromea and Rhizopus stolonifer.

O Presente estudo foi realizado para investigar os efeitos da radiação gama sobre a microflora epífita e amadurecimento das bananas Cavendish Anão verde colhidas no estádio de três quartos da maturidade. As bananas verdes maduros foram irradiadas usando Cobalto-60 como fonte de irradiação a diferentes dosagens de 0,5, 0,75 e 1,0 kGy. A vida média de ambos os grupos experimental e de controlo de frutas foi analisada sob as condições ambientes. Para todos os tratamentos a potenciais microbiana, o percentual decadência e do comportamento do amadurecimento dos frutos foram recorded.Results revelou que as doses de radiação aplicadas reduziu a incidência de podridões, atrasou processo de amadurecimento e inibir significativamente o crescimento microbiano (contagem de bactérias e fungos total), assim aumentar a vida de prateleira das bananas. dose de irradiação de 1,0 kGy foi encontrada como sendo a dose mais eficaz para manter positivamente as bananas armazenada sob condições ambientes. A vida média de bananas foi prorrogado por 14 dias. A identificação do bacteriaeaceae entérico através de API 20 E tiras revelou a presença de Shigella sonnie sobre a superfície do fruto, juntamente com Escherichia coli e um nonfermentor spp. A deterioração dominante causando fungos identificados foram Aspergillus niger, Aspergillus flavus, Collotrichum musae, Fusarium oxysporum, Mucor spp, Lasiodiplodia theobromea e Rhizopus stolonifer.