Effect of phenolic monomers on biomass and hydrolytic enzyme activities of an anaerobic fungus isolated from wild nil gai (Baselophus tragocamelus)

Abstract

Aims: To test the anaerobic fungus, Piromyces sp. FNG5, for its tolerance to phenolic monomers released in the rumen by degradation of lignocellulosic poor-quality feeds. Methods and Results: Effects of phenolic monomers on biomass and fibrolytic enzyme activities of a pure culture of lignocellulolytic anaerobic fungus (Piromyces sp. FNG5) isolated from faeces of wild nil gai (blue bull, Baselophus tragocamelus) were evaluated. There was a reduction in fungal biomass at 1 mM M concentration of catechol with complete inhibition at 10 mM M. p-Coumaric acid caused a reduction in biomass at 10 mM M and no growth was observed above 20 mM M concentration. The fungal isolate could tolerate up to 5 mM M of ferulic acid without any reduction in biomass level, and was able to grow to some extent up to the highest level of ferulic acid tested (20 mM M). Vanillic acid had no effect on biomass of the fungus even up to 50 mM M level. The phenolic monomers varied in their potential to inhibit the secretion of carboxymethyl cellulase, xylanase, b-glucosidase and acetyl esterase activities with catechol being the most inhibitory and vanillic acid being the least inhibitory. After 14 days of incubation, 38AE49-65AE14% p-Coumaric acid, 65AE22-74AE10% ferulic acid and 34AE13-66AE78% vanillic acid disappeared from the medium under anaerobic conditions. Conclusions, Significance and Impact of the Study: It is concluded that the anaerobic fungus Piromyces sp. FNG5 is tolerant to phenolic monomers and has ability to degrade them. Therefore, such anaerobic fungi may play an important role in fibre degradation in the rumen.

Effect of anaerobic fungi on in vitro feed digestion by mixed rumen microflora of buffalo

“…Carboxymethylcellulase (CMCase) and xylanase activities were estimated as described earlier [14][15][16]. The reaction mixture used for the estimation of these enzymes contained: 1.0 mL phosphate buffer (pH 6.8, 0.1 M), 0.5 mL substrate (1% carboxymethylcellulose and 0.25% xylan from oat spelt) and 0.5 mL enzyme; incubated at 39 °C for 1 h for CMCase and 30 min for xylanase.…”

Phenotypic and phylogentic characterisation of tannin degrading/tolerating bacterial isolates from the rumen of goats fed on pakar (Ficus infectoria)leaves

“…Nelson et al (1995) tested ferulic acid, pyrogallol, gallic acid, and p-coumaric acid upto 40 mM concentration in the medium and found most of the isolates were able to tolerate gallic and vannilic acid but they were not able to tolerate ferulic acid and pyrogallol at the highest concentration. The fungal isolates from neelgai also showed variability in the tolerance to phenolic monomers (Paul et al 2004). …”

Effect of adding an anaerobic fungal culture isolated from a wild blue bull (Boselophus tragocamelus) to rumen fluid from buffaloes on in vitro fibrolytic enzyme activity, fermentation and degradation of tannins and tannin‐containing Kachnar tree (Bauhinia variegata) leaves and wheat straw

“…In one of our earlier studies it has been observed that an anaerobic fungus (Piromyces sp FNG5) isolated from the faeces of the wild blue bull (Boselophus tragocamelus) has high lignocellulolytic enzyme-producing ability and degrades phenolic monomers extensively. 10 Addition of culture of this fungal isolate significantly increased the lignocellulolytic ability of mixed rumen microflora of buffalo under both in vitro and in vivo conditions. 11 As the tannins are also phenolic compounds and as the fungal isolate was obtained from a wild herbivorous animal (blue bull) which survives on poor-quality tannin-rich hard stem herbages, our hypothesis was that the fungal isolate might have the ability to degrade or tolerate tannins and that introduction of such fungus into the rumen of domestic buffaloes (which had had no prior exposure to tannins) would enhance digestion of tannin containing feed.…”

“…The fungal isolate had very high lignocellulolytic enzyme-producing ability and degraded phenolic monomers extensively. 10,11 The fungal isolate exhibited the highest carboxymethyl cellulase, xylanase, β-glucosidase, feruloyl esterase, p-coumaroyl esterase, protease and acetyl esterase activity among 32 isolates from Indian domestic (buffalo, goat and sheep) and wild (hog deer, spotted deer, black buck and blue bull) ruminants. The fungal strain was maintained by weekly transfer of 5% culture to fresh liquid medium containing 0.02% cellobiose and 0.5% wheat straw as carbon sources.…”

“…24 Acetyl esterase activity was estimated by the method of Huggins and Lapides 25 with some modifications as described earlier. 10 The activities of CMCase and xylanase were expressed as nmol glucose and xylose, respectively, released per minute under the assay conditions (mIU mL −1 ). The activities of β-glucosidase and acetyl esterase were expressed as nmol pnitrophenol released per min under the assay conditions (mIU mL −1 ).…”