Screening and characterization of amylase and cellulase activities in psychrotolerant yeasts

Abstract

BackgroundAmylases and cellulases have great potential for application in industries such as food, detergent, laundry, textile, baking and biofuels. A common requirement in these fields is to reduce the temperatures of the processes, leading to a continuous search for microorganisms that secrete cold-active amylases and cellulases. Psychrotolerant yeasts are good candidates because they inhabit cold-environments. In this work, we analyzed the ability of yeasts isolated from the Antarctic region to grow on starch or carboxymethylcellulose, and their potential extracellular amylases and cellulases.ResultAll tested yeasts were able to grow with soluble starch or carboxymethylcellulose as the sole carbon source; however, not all of them produced ethanol by fermentation of these carbon sources. For the majority of the yeast species, the extracellular amylase or cellulase activity was higher when cultured in medium supplemented with glucose rather than with soluble starch or carboxymethylcellulose. Additionally, higher amylase activities were observed when tested at pH 5.4 and 6.2, and at 30–37 °C, except for Rhodotorula glacialis that showed elevated activity at 10–22 °C. In general, cellulase activity was high until pH 6.2 and between 22–37 °C, while the sample from Mrakia blollopis showed high activity at 4–22 °C. Peptide mass fingerprinting analysis of a potential amylase from Tetracladium sp. of about 70 kDa, showed several peptides with positive matches with glucoamylases from other fungi.ConclusionsAlmost all yeast species showed extracellular amylase or cellulase activity, and an inducing effect by the respective substrate was observed in a minor number of yeasts. These enzymatic activities were higher at 30 °C in most yeast, with highest amylase and cellulase activity in Tetracladium sp. and M. gelida, respectively. However, Rh. glacialis and M. blollopis displayed high amylase or cellulase activity, respectively, under 22 °C. In this sense, these yeasts are interesting candidates for industrial processes that require lower temperatures.Electronic supplementary materialThe online version of this article (doi:10.1186/s12866-016-0640-8) contains supplementary material, which is available to authorized users.

Functional and Comparative Genomics of Niche-Specific Adapted ActinomycetesKocuria rhizophilaStrain D2 Isolated from Healthy Human Gut

“…We tested the isolate for nine exoenzymes by standard microbiological methods viz. Phosphatase by Pikovasky’s agar base (52), lipase by tributyrin agar base (53), urease by urease agar base (54), protease by skimmed milk agar (55), gelatinase by gelatin medium (56), cellulase by CMC agar (57), amylase by starch iodine test (58), Nitrate reductase by colour change method (59) and catalase by effervescence of 6% H 2 O 2 (60). Carbohydrate utilization was conducted by HiCarbohydrateTM Kit (Sigma, India) consisting of thirty-four carbohydrates with respect to manufactures instructions.…”

Cold-adapted enzymes produced by fungi from terrestrial and marine Antarctic environments

“…The production of cellulases has been reported by Antarctic fungi isolated from marine sponges [34], soil [13,66], ornithogenic soils [7,77], and from wood and other organic materials [89][90][91]. The introduction of wood and other organic materials for human survival by early explorers may have introduced exogenous fungi and new nutrient sources for the indigenous fungi.…”

Molecular characterization and growth optimization of halo-tolerant amylase producing bacteria isolated from salt mines of Karak, Pakistan

“…The agarose gel electrophoresis was performed according the standard protocol [10]. The 16S rRNA gene amplification of the bacterial isolates was carried out through PCR by using the universal 16s primers 9F (5'-GAGTTTGATCCTGGCTCAG-3') and 1510R (5' GGCTACCTTGTTACGA-3') The PCR was done through optimized PCR program; initial denaturation 2 minutes, 94 0 C, annealing temperature 1 minute, 52 0 C, while extension for 2 minutes at 72 0 C. For the final extension the time was 10 minutes and temperature was 72 0 C. The overall reaction was repeated for 35 cycles.…”