Detoxification of corn stalk pretreated with calcium hydroxide for true protein accumulation

Alkaline pretreatment is essential in lignin degradation, but the inhibitors produced in this process affect microbial growth. To overcome the impacts of the phenolic compounds, detoxification was applied to corn stalk pretreated with calcium hydroxide.The results showed that ferulic acid degradation rate can reach 85.11% by laccase at the optimal conditions. Phanerochaete chrysosporium degraded most vanillin (77.19%) and p-hydroxybenzaldehyde (63.82%) but the degradation of ferulic acid (15.34%) was relatively weak. Laccase combined with Phanerochaete chrysosporium detoxified most of the phenolic compounds including 2- methoxy-4-vinylphenol (88.46%) and salicylic acid (58.13%) that hardly decompose alone after calcium hydroxide pretreatment in this study. These results inferred that Phanerochaete chrysosporium might generate some substance during the spore germination and growth period which may cooperate with laccase to decompose the phenolic compounds. After the fermentation of detoxified corn stalk by Neurospora crassa, the true protein content was increased by 2.73 times, and 21.17% lignin was degraded.

OPTIMASI PRODUKSI SENYAWA VANILIN DARI BIOKONVERSI LIGNOSELULOSA TANDAN KOSONG KELAPA SAWIT DENGAN PHANEROCHAETE CHRYSOSPORIUM MENGGUNAKAN RESPONSE SURFACE METHOD

Limbah tandan kosong kelapa sawit (TKKS) merupakan limbah hasil produksi minyak sawit yang memiliki kandungan lignoselulosa (lignin, selulosa, hemiselulosa) tinggi, dapat dimanfaatkan untuk produksi senyawa aromatik vanilin dengan menggunakan jamur Phanerochaete chrysosporium dan pelarut etil asetat. Diketahui pelarut etil asetat dan lama ekstraksi berpengaruh terhadap kadar vanilin dan yield vanilin dengan Response Surface Methode (RSM) terdiri dari 4 faktor yang digunakan untuk mengukur sejauh mana faktor-faktor tersebut saling berpengaruh terhadap kadar vanilin. Regresi terdiri dari 13 titik faktorial dengan 6 titik aksial, dan 7 titik tengah melalui softwere Design Expert 7.0.0. Faktor-faktor optimasi digabung untuk mendapatkan nilai optimum untuk menghasilkan kadar dan yield vanilin yang bagus. Hasil penelitian optimasi RSM volume pelarut etil asetat yaitu 100,36 mL dan lama ekstraksi yaitu 120,27 menit yang digunakan dalam penelitian TKKS dengan nilai validasi optimal yang didapatkan yaitu kadar vanilin mendekati hasil prediksi sebesar 0,015% dan yield vanilin sebesar 11,862 µg/g. Hasil dalam penelitian ini menunjukkan penggunaan bio-pretreatment Phanaerocaete chrysosporium sebagai biokonversi TKKS menghasilkan vanilin dapat menekan biaya besar dan meningkatkan nilai fungsi dari limbah TKKS

Influence of sucrosis on the degradation of pesticide by white rot fungus

The influence of sucrose on the removal of Paraquat (PQT) in synthetic aqueous medium was evaluated by Phanerochaete chrysosporium. Initially, a toxicity test was performed on plates containing paraquat at concentrations of 1, 5, 10, 20 and 30 mg.L-1. Then, they were carried out in batches - agitated batch (RBA) and sequential batch (RBS). Four reactors were submitted, containing medium with 30 mg.L-1 of paraquat, under a reaction time of 144 h, the reactors being RBA-2 and RBS-2 with the addition of 2 gL-1 of sucrose, and without the adding sucrose to the RBA-0 and RBS-0 reactors. In all reactors, paraquat was removed, but in RBS-0, the best mean removal efficiency was obtained (41.1 ± 0.89%). The best values ​​of apparent speed of degradation (k) were found in reactors with sucrose RBA-2 and RBS-2, 0.015 ± 0.002 h-1 and 0.018 ± 0.002 h-1, respectively, indicating that the addition of sucrose influenced the speed removal of paraquat. It was also verified that the pollutant was not completely removed by adsorption to fungal biomass, which microorganisms predominated in the medium at the end of the treatment, demonstrating their role in the paraquat bioremediation process. Therefore, the addition of sucrose influenced the removal speed of the PQT and COD, but not the removal efficiency.