Conversion of cassava leaf to bioavailable, high‐protein yeast cell biomass

Abstract

BACKGROUND Cassava leaves are an abundant global agricultural residue because the roots are a major source of dietary carbohydrates. Although cassava leaves are high in protein, the protein is not bioavailable. This work aimed to convert cassava leaves to a bioavailable protein‐rich animal feed ingredient using high‐protein yeasts. RESULTS The structural proteins (ca 200 g kg−1 d.b.) from sundried cassava leaves were solubilized by mild alkali pretreatment, and the resulting cassava leaf hydrolysate (CLH) was used to screen for growth of 46 high‐protein yeasts from 30 species. Promising candidates from the initial screen cultivated at a 10 mL scale demonstrated increases in relative abundance of essential amino acids over that of CLH. In particular, lysine, growth‐limiting for some livestock, was increased up to 226% over the CLH content. One yeast, Pichia kudriavzevii UCDFST 11‐602, was grown in 3 L of CLH in a bioreactor to examine the scale‐up potential of the yeast protein production. While glucose was completely consumed, yeast growth exited log phase before depleting either carbon or nitrogen, suggesting other growth‐limiting factors at the larger scale. CONCLUSIONS High‐value animal feed with enriched essential amino acid profiles can be produced by yeasts grown on agricultural residues. Yeasts convert structural protein solubilized from cassava leaves to essential amino acid‐enriched, digestible protein. The low carbohydrate content of the leaves (ca 200 g kg−1 d.b.), however, necessitated glucose supplementation for yeast growth. © 2018 Society of Chemical Industry

Evaluation of nutritional properties, and consumer preferences of legume-fortified cassava leaves for low-income households in Zambia

“…The protein content of the plain Cassava leaves sample (501) recorded the highest value in comparison to the legume fortified variants. This affirms several reports of the relatively high protein content of cassava leaves (Hidayat et al, 2016;Lancaster & Brooks, 1983;Phuc et al, 2000).However, the protein digestibility is low due to high fibre content and complex formation with tannins through hydrogen bonding and covalent linkages (Natesh et al, 2017), thereby lowering its bioavailability (Boundy-Mills et al, 2019;Morales et al, 2018). Thus, an important reason why cassava leaves should be fortified with legumes rich in bioavailable protein before consumption.…”

“…Cassava leaf, though a highly nutritious vegetable, contains a considerable amount of antinutrients and toxic substances which makes it undergo rigorous processing methods in order to bring it to a permissible range that is safe for human consumption (Latif and Müller, 2015). Legumes are added to cassava leaf meal to make up for the assumed nutrient loss during detoxification as it has been mentioned earlier that protein in cassava leaf is not bioavailable (Boundy-Mills et al, 2019). Thus, cassava leaf meal fortified with legumes is a positive way to diet diversification and promotion of a highly nutritious relish in Zambia.…”

Brewing rich 2‐phenylethanol beer from cassava and its producing metabolisms in yeast

“…Meanwhile, the lack of high value deep‐processed cassava products with large market demand has greatly restricted the cultivation of cassava in Asia and America. The main measures to solve the dilemma of the cassava industry are to develop new uses of cassava, exploit new products of cassava processing, and improve the added value of new products of cassava processing 16–19 …”

Oligosaccharides in straw hydrolysate could improve the production of single‐cell protein with Saccharomyces cerevisiae

“…Single‐cell proteins can be produced from agricultural residues and industrial wastes 3‐7 . Gervasia et al .…”

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