Abstract

SANCHEZ-SANTILLAN, Paulino et al. Use of activated carbon to preserve lyophilized cellulolytic bacteria. Agrociencia [online]. 2016, vol.50, n.5, pp.575-582. ISSN 2521-9766.

Successful conservation of microorganisms is attained by preventing contamination during the process and optimizing high survival and genetic stability. The objective of this study was to evaluate the use of activated carbon as a preserver of cellulolytic bacteria during the process of lyophilization. The cellulolytic bacterial culture was obtained from four transfers of fresh ruminal liquid in culture media and Whatman paper. As a lyoprotectant, activated carbon (CA) was added before lyophilizing and compared with a control treatment without lyoprotectant (SL). The lyophilized bacteria were reactivated in culture media; characteristics of both media and bacteria were measured. The reactivated bacteria were the inoculum in the evaluation of in vitro dry matter degradation (%DMDEG) and production of volatile fatty acids (VFA). The experimental design was completely randomized repeated in time. The CA treatment degraded 83.3% of the Whatman paper during reactivation. The oxide-reduction potential and culture media pH were not different between treatments (p>0.05). The CA treatment showed higher concentration of bacteria (9.58×108 bacteria mL-1), greater degradation of substrates (32.75 %DMDEG), and higher production of acetic (54.50 mM L-1) and butyric (12.74 mM L-1) acids, compared to the SL treatment (p≤0.05). Propionic acid and total VFA showed significant treatment-time interaction. The CA treatment produced more total VFA (p≤0.05), but propionic acid was different only between treatments at the first measurement time (p≤0.05). Activated carbon has characteristics that preserve cellulolytic bacteria for lyophilization.

Keywords : Lyoprotectant; ruminal bacteria; in vitro; lyophilization; degradation.

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