Faculty of Food Technology and Biotechnology, University of Zagreb
Abstract
Chromium(III) is an essential trace element for humans and animals. Pleutorus cornucopiae SD-01 is a nutritional and functional mushroom containing many kinds of bioactive ingredients. The aims of this work are to optimize the conditions of P. cornucopiae SD-01 cultivation with Cr enrichment in submerged culture by determining the dry cell mass, Cr content in mycelia and the rate of Cr enrichment, and to analyze the amino acid composition of Cr-enriched mycelia. The optimal medium contained (in g/L): potato 200, sucrose 25, yeast extract 4, KH2PO4 1 and MgSO4·7H2O 1. The optimum parameters of liquid culture were temperature 25 °C, cultivation time 6 days, the volume of the medium 100 mL, rotation speed 160 rpm and initial pH=6.5. Under the optimized conditions, the values of the dry cell mass, Cr content in mycelia and the rate of Cr enrichment were (6.63±0.35) g/L, (3670±211) μg/g and (12.15±1.01) % respectively, which were by (23.23±1.22), (18.19±1.06) and (45.68±2.67) % respectively, higher than those in the control. Chromium(III) in Cr-enriched mycelia was mainly combined with protein and polysaccharide. The contents of total amino acids and essential amino acids in Cr-enriched mycelia were increased by (31.25±0.58) and (44.26±0.76) %, respectively.Trovalentni je krom esencijalni element u tragovima, potreban za rast ljudi i životinja. Pleurotus cornucopiae SD-01 hranjiva je gljiva funkcionalnih svojstava, koja sadrži mnoge bioaktivne komponente. Svrha je ovoga rada bila optimirati uvjete uzgoja P. cornucopiae SD-01 u podlozi obogaćenoj kromom, i to određivanjem suhe stanične mase, udjela kroma u miceliju i stupnja obogaćivanja micelija, te analizirati aminokiselinski sastav micelija obogaćenog kromom. Optimalni sastav podloge bio je (u g/L): krumpir 200, saharoza 25, kvaščev ekstrakt 4, KH2PO4 1 i MgSO4·7H2O 1. Utvrđeni su optimalni parametri rasta: temperatura 25 °C, vrijeme uzgoja 6 dana, volumen podloge 100 mL, brzina rotacije 160 rpm i početni pH=6,5. U tim su uvjetima dobivene sljedeće vrijednosti: suha stanična masa od (6,63±0,35) g/L, veća za (23,23±1,22) %; udio kroma u miceliju od (3670±211) mg/g, veći za (18,19±1,06) % i stupanj obogaćivanja micelija kromom od (12,15±1,01) %, što je za (45,68±2,67) % više nego u kontrolnom uzorku. Utvrđeno je da se trovalentni krom u miceliju uglavnom veže za proteine i ugljikohidrate. Ukupni se udio aminokiselina u takvom obogaćenom miceliju povećao za (31,25±0,58) %, a udio esencijalnih aminokiselina za (44,26±0,76) %
