Co-Production of Lactic Acid and Ethanol Using Rhizopus Sp. From Hydrolyzed Inedible Cassava Starch and Leaves

Abstract

Production of lactic acid and ethanol from inedible cassava starch and leaves was investigated. Prior to fermentation, hydrolysis of the starch and leaves was conducted. Hydrolysis was optimized by manipulating at three levels each four particular factors, namely acid concentration, starch concentration, temperature, and reaction time. Maximum glucose yield of 0.96 g/g was obtained when 2.5% (w/v) of cassava leaves with 2.5% (w/v) of starch was hydrolyzed using 0.20 M of nitric acid at 160oC of temperature for 10 min. The potential of hydrolyzed cassava starch and leaves was then investigated for lactic acid production using fungal Rhizopus sp. The fermentation process was then conducted in shake flask by varying four factors at three levels each. Maximum lactic acid and ethanol yields of 0.95 g/g and 0.52 g/g, respectively, were achieved at different optimum conditions.  Lactic acid production was found to be linked to a decrease in ethanol production. Design Expert v6.0.8 was used to aid in the design of the experiment using Taguchi’s methodology.

Response Surface Optimization of Rhizopus sp. Immobilization onto Loofah Sponge Using Potato Dextrose

“…Rhizopus sp. was previously isolated from ragi tapai and grown on potato dextrose agar (PDA) under an incubation temperature of 37°C for 7 days [14]. After growth and sporulation, 15 ml distilled water was added to each agar plate, which was then scratched to release spores.…”

Kecambah: Agen penghidrolisis pati yang potensial

“…Kemampuan hidrolisis pati secara kimiawi dengan HCl sangat rendah. Pada penelitian Azmi et al (2016), pati dihidrolisis dengan asam menggunakan suhu 160℃ agar menghasilkan produk/gula pereduksi yang tinggi. Sementara pada percobaan ini, pati dengan campuran HCl diinkubasi pada suhu 100℃.…”

Synthesis L-Lactic Acid From Fermentation of Cassava Pulp by Using Tempeh Inoculum

“…The fungi usually cultivated in the inoculum such as R. oligosporus, R. oryzae, R. stolonifer, and R. arrhizus [9]. Some works reported that R.oryzae and R.oligosporus could utilize various agricultural residues such as L-LA, fumaric acid, and ethanol to produce LA [10,11]. The use of Rhizopus has several advantages; it can suppress downstream processes because of the ease of separating mould filaments.…”

“…The use of Rhizopus has several advantages; it can suppress downstream processes because of the ease of separating mould filaments. Previous researchers have studied LA fermentation using strain Rhizopus sp, with different carbon sources, nitrogen sources, and operating conditions (pH, temperature, volume, and rotation speed) but mostly using acid hydrolysis to convert polysaccharides into monosaccharides [10][11][12]. Acid hydrolysis has drawbacks such as corrosion-resistant tools, carbohydrate degradation and product recombination [8].…”