Abstract
Agroindustry residues can be used to produce valuable chemicals such as lactic acid, which is a primary chemical platform with many industrial applications. Biotechnological processes are the main approach of lactic acid production; however, culture media has an important impact on their costs. As a result, researchers are exploring various methods of production that use residual or waste biomass as raw materials, most of which are rich in lignocellulose. Nevertheless, starch and micronutrients such as those contained in avocado seeds stand out as promising feedstock for the bioprocess as well. In this study, the lactogenic Escherichia coli strain JU15 was evaluated for producing d-lactate using an avocado seed hydrolysate medium in a controlled stirred-tank bioreactor. The highest lactic acid concentration achieved was 37.8 g L−1 using 120 g L−1 as the content of initial reducing sugars. The results showed that d-lactate can be produced from avocado seed, which hydrolysates to 0.52 g L−1 h−1 using the engineered E. coli JU15. This study may serve as a starting point to further develop bioprocesses for producing metabolites using avocado seed hydrolysates.
Highlights
Residual agroindustry has two main groups: lignocellulosic and starch-enriched materials.The first one corresponds principally to crop residues, and the second one corresponds to tubercles and their fruit seeds, such as the avocado seed
In a previous study [26], it has been demonstrated that avocado seed hydrolysate (ASH) supplemented with 5× M9 minimal medium salts was able to support the growth of E. coli even better than LB medium
It is seen that the E. coli strain JU15 is capable of using the nutrients that are available following
Summary
Residual agroindustry has two main groups: lignocellulosic and starch-enriched materials. The first one corresponds principally to crop residues, and the second one corresponds to tubercles and their fruit seeds, such as the avocado seed. Avocado is mainly produced in North and Central America; in México, avocado is a main agroindustry commodity exceeding a global production of 1.9 million metric tons (MMT) in 2018 [1]. The industrial processing of this fruit, mostly for guacamole and oil production, yields considerable amounts of residues such as the biomass constituted by husks and seeds; the latter accounts for up to 26% of the fruit fresh mass [2]. The composition of the lyophilized avocado peeled seeds (Hass variety) mostly consists of carbohydrates (48–79.5%) and other minimal components, among them: lipids (5.5–15%), proteins (3.4–19%), crude fiber (4.0%), ashes (0.8–4.2%), and moisture (13.2%) [2,3]. An ultimate analysis of seeds results in: total carbon (85.9%), hydrogen (0.55%), nitrogen (3.17%), oxygen (9.49%), sulfur (0.07%), volatile matter (27.55%), and biologically important minerals such as potassium, calcium, magnesium, iron, zinc, phosphorus, and silicon [3,4]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
